diff --git a/src/tests/cli.rs b/src/tests/cli.rs
index a376499..9e9527b 100644
--- a/src/tests/cli.rs
+++ b/src/tests/cli.rs
@@ -2,8 +2,15 @@ use assert_cmd::prelude::*;
 use std::env;
 use std::process::Command;
 
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
 #[test]
-fn print_version() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_print_version() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd.arg("-V").output().unwrap();
 
@@ -23,7 +30,7 @@ fn print_version() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn bad_input_empty_target() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_bad_input_empty_target() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd.arg("").output().unwrap();
 
@@ -43,7 +50,7 @@ fn bad_input_empty_target() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn bad_input_data_url() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_bad_input_data_url() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd.arg("data:,Hello%2C%20World!").output().unwrap();
 
@@ -63,7 +70,7 @@ fn bad_input_data_url() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn isolate_data_url() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_isolate_data_url() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd
         .arg("-I")
@@ -89,7 +96,7 @@ fn isolate_data_url() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn remove_css_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_remove_css_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd
         .arg("-c")
@@ -116,7 +123,7 @@ fn remove_css_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn remove_frames_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_remove_frames_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd
         .arg("-f")
@@ -142,7 +149,7 @@ fn remove_frames_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn remove_images_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_remove_images_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd
         .arg("-i")
@@ -174,7 +181,7 @@ Hi\
 }
 
 #[test]
-fn remove_js_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_remove_js_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd
         .arg("-j")
@@ -203,7 +210,7 @@ fn remove_js_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn local_file_target_input() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_local_file_target_input() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let cwd_normalized: String =
         str!(env::current_dir().unwrap().to_str().unwrap()).replace("\\", "/");
@@ -251,7 +258,8 @@ fn local_file_target_input() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn local_file_target_input_absolute_target_path() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_local_file_target_input_absolute_target_path() -> Result<(), Box<dyn std::error::Error>>
+{
     let cwd = env::current_dir().unwrap();
     let cwd_normalized: String =
         str!(env::current_dir().unwrap().to_str().unwrap()).replace("\\", "/");
@@ -306,7 +314,7 @@ fn local_file_target_input_absolute_target_path() -> Result<(), Box<dyn std::err
 }
 
 #[test]
-fn local_file_url_target_input() -> Result<(), Box<dyn std::error::Error>> {
+fn passing_local_file_url_target_input() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let cwd = env::current_dir().unwrap();
     let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
@@ -369,8 +377,8 @@ fn local_file_url_target_input() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 #[test]
-fn security_disallow_local_assets_within_data_url_targets() -> Result<(), Box<dyn std::error::Error>>
-{
+fn passing_security_disallow_local_assets_within_data_url_targets(
+) -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
     let out = cmd
         .arg("data:text/html,%3Cscript%20src=\"src/tests/data/local-script.js\"%3E%3C/script%3E")
diff --git a/src/tests/html/get_node_name.rs b/src/tests/html/get_node_name.rs
new file mode 100644
index 0000000..2fbdc35
--- /dev/null
+++ b/src/tests/html/get_node_name.rs
@@ -0,0 +1,49 @@
+use crate::html;
+use html5ever::rcdom::{Handle, NodeData};
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn get_node_name() {
+    let html = "<!doctype html><html><HEAD></HEAD><body><div><P></P></div></body></html>";
+    let dom = html::html_to_dom(&html);
+    let mut count = 0;
+
+    fn test_walk(node: &Handle, i: &mut i8) {
+        *i += 1;
+
+        match &node.data {
+            NodeData::Document => {
+                for child in node.children.borrow().iter() {
+                    test_walk(child, &mut *i);
+                }
+            }
+            NodeData::Element { ref name, .. } => {
+                let node_name = name.local.as_ref().to_string();
+                let parent = html::get_parent_node(node);
+                let parent_node_name = html::get_node_name(&parent);
+                if node_name == "head" || node_name == "body" {
+                    assert_eq!(parent_node_name, "html");
+                } else if node_name == "div" {
+                    assert_eq!(parent_node_name, "body");
+                } else if node_name == "p" {
+                    assert_eq!(parent_node_name, "div");
+                }
+
+                for child in node.children.borrow().iter() {
+                    test_walk(child, &mut *i);
+                }
+            }
+            _ => (),
+        };
+    }
+
+    test_walk(&dom.document, &mut count);
+
+    assert_eq!(count, 7);
+}
diff --git a/src/tests/html/is_icon.rs b/src/tests/html/is_icon.rs
new file mode 100644
index 0000000..334cec4
--- /dev/null
+++ b/src/tests/html/is_icon.rs
@@ -0,0 +1,50 @@
+use crate::html;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_icon() {
+    assert!(html::is_icon("icon"));
+}
+
+#[test]
+fn passing_shortcut_icon_capitalized() {
+    assert!(html::is_icon("Shortcut Icon"));
+}
+
+#[test]
+fn passing_icon_uppercase() {
+    assert!(html::is_icon("ICON"));
+}
+
+#[test]
+fn passing_mask_icon() {
+    assert!(html::is_icon("mask-icon"));
+}
+
+#[test]
+fn passing_fluid_icon() {
+    assert!(html::is_icon("fluid-icon"));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_stylesheet() {
+    assert!(!html::is_icon("stylesheet"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!html::is_icon(""));
+}
diff --git a/src/tests/html/mod.rs b/src/tests/html/mod.rs
new file mode 100644
index 0000000..bacc18a
--- /dev/null
+++ b/src/tests/html/mod.rs
@@ -0,0 +1,4 @@
+mod get_node_name;
+mod is_icon;
+mod stringify_document;
+mod walk_and_embed_assets;
diff --git a/src/tests/html/stringify_document.rs b/src/tests/html/stringify_document.rs
new file mode 100644
index 0000000..2089996
--- /dev/null
+++ b/src/tests/html/stringify_document.rs
@@ -0,0 +1,188 @@
+use crate::html;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_div_as_root_element() {
+    let html = "<div><script src=\"some.js\"></script></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = false;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<html><head></head><body><div><script src=\"some.js\"></script></div></body></html>"
+    );
+}
+
+#[test]
+fn passing_full_page_with_no_html_head_or_body() {
+    let html = "<title>Isolated document</title>\
+                <link rel=\"something\" href=\"some.css\" />\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+                <div><script src=\"some.js\"></script></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = true;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<html>\
+            <head>\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:;\"></meta>\
+                <title>Isolated document</title>\
+                <link rel=\"something\" href=\"some.css\">\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+            </head>\
+            <body>\
+                <div>\
+                    <script src=\"some.js\"></script>\
+                </div>\
+            </body>\
+         </html>"
+    );
+}
+
+#[test]
+fn passing_doctype_and_the_rest_no_html_head_or_body() {
+    let html = "<!doctype html>\
+                <title>Unstyled document</title>\
+                <link rel=\"stylesheet\" href=\"main.css\"/>\
+                <div style=\"display: none;\"></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = true;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = false;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<!DOCTYPE html>\
+         <html>\
+         <head>\
+         <meta http-equiv=\"Content-Security-Policy\" content=\"style-src 'none';\"></meta>\
+         <title>Unstyled document</title>\
+         <link rel=\"stylesheet\" href=\"main.css\">\
+         </head>\
+         <body><div style=\"display: none;\"></div></body>\
+         </html>"
+    );
+}
+
+#[test]
+fn passing_doctype_and_the_rest_no_html_head_or_body_forbid_frames() {
+    let html = "<!doctype html>\
+                <title>Frameless document</title>\
+                <link rel=\"something\"/>\
+                <div><script src=\"some.js\"></script></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = false;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<!DOCTYPE html>\
+            <html>\
+            <head>\
+            <meta http-equiv=\"Content-Security-Policy\" content=\"frame-src 'none';child-src 'none';\"></meta>\
+            <title>Frameless document</title>\
+            <link rel=\"something\">\
+            </head>\
+            <body><div><script src=\"some.js\"></script></div></body>\
+            </html>"
+    );
+}
+
+#[test]
+fn passing_doctype_and_the_rest_all_forbidden() {
+    let html = "<!doctype html>\
+                <title>no-frame no-css no-js no-image isolated document</title>\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+                <link rel=\"stylesheet\" href=\"some.css\">\
+                <div>\
+                <script src=\"some.js\"></script>\
+                <img style=\"width: 100%;\" src=\"some.png\" />\
+                <iframe src=\"some.html\"></iframe>\
+                </div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_isolate: bool = true;
+    let opt_no_css: bool = true;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = true;
+    let opt_no_images: bool = true;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<!DOCTYPE html>\
+            <html>\
+                <head>\
+                    <meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:; style-src 'none'; frame-src 'none';child-src 'none'; script-src 'none'; img-src data:;\"></meta>\
+                    <title>no-frame no-css no-js no-image isolated document</title>\
+                    <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+                    <link rel=\"stylesheet\" href=\"some.css\">\
+                </head>\
+                <body>\
+                    <div>\
+                        <script src=\"some.js\"></script>\
+                        <img style=\"width: 100%;\" src=\"some.png\">\
+                        <iframe src=\"some.html\"></iframe>\
+                    </div>\
+                </body>\
+            </html>"
+    );
+}
diff --git a/src/tests/html.rs b/src/tests/html/walk_and_embed_assets.rs
similarity index 54%
rename from src/tests/html.rs
rename to src/tests/html/walk_and_embed_assets.rs
index fe68833..716e6c8 100644
--- a/src/tests/html.rs
+++ b/src/tests/html/walk_and_embed_assets.rs
@@ -1,64 +1,17 @@
 use crate::html;
-use html5ever::rcdom::{Handle, NodeData};
 use html5ever::serialize::{serialize, SerializeOpts};
 use reqwest::blocking::Client;
 use std::collections::HashMap;
 
-#[test]
-fn is_icon() {
-    assert_eq!(html::is_icon("icon"), true);
-    assert_eq!(html::is_icon("Shortcut Icon"), true);
-    assert_eq!(html::is_icon("ICON"), true);
-    assert_eq!(html::is_icon("mask-icon"), true);
-    assert_eq!(html::is_icon("fluid-icon"), true);
-    assert_eq!(html::is_icon("stylesheet"), false);
-    assert_eq!(html::is_icon(""), false);
-}
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
 
 #[test]
-fn get_parent_node_get_node_name() {
-    let html = "<!doctype html><html><HEAD></HEAD><body><div><P></P></div></body></html>";
-    let dom = html::html_to_dom(&html);
-    let mut count = 0;
-
-    fn test_walk(node: &Handle, i: &mut i8) {
-        *i += 1;
-
-        match &node.data {
-            NodeData::Document => {
-                for child in node.children.borrow().iter() {
-                    test_walk(child, &mut *i);
-                }
-            }
-            NodeData::Element { ref name, .. } => {
-                let node_name = name.local.as_ref().to_string();
-                let parent = html::get_parent_node(node);
-                let parent_node_name = html::get_node_name(&parent);
-                if node_name == "head" || node_name == "body" {
-                    assert_eq!(parent_node_name, "html");
-                } else if node_name == "div" {
-                    assert_eq!(parent_node_name, "body");
-                } else if node_name == "p" {
-                    assert_eq!(parent_node_name, "div");
-                }
-
-                println!("{}", node_name);
-
-                for child in node.children.borrow().iter() {
-                    test_walk(child, &mut *i);
-                }
-            }
-            _ => (),
-        };
-    }
-
-    test_walk(&dom.document, &mut count);
-
-    assert_eq!(count, 7);
-}
-
-#[test]
-fn walk_and_embed_assets() {
+fn passing_basic() {
     let cache = &mut HashMap::new();
 
     let html = "<div><P></P></div>";
@@ -95,7 +48,7 @@ fn walk_and_embed_assets() {
 }
 
 #[test]
-fn walk_and_embed_assets_ensure_no_recursive_iframe() {
+fn passing_ensure_no_recursive_iframe() {
     let html = "<div><P></P><iframe src=\"\"></iframe></div>";
     let dom = html::html_to_dom(&html);
     let url = "http://localhost";
@@ -131,7 +84,7 @@ fn walk_and_embed_assets_ensure_no_recursive_iframe() {
 }
 
 #[test]
-fn walk_and_embed_assets_ensure_no_recursive_frame() {
+fn passing_ensure_no_recursive_frame() {
     let html = "<frameset><frame src=\"\"></frameset>";
     let dom = html::html_to_dom(&html);
     let url = "http://localhost";
@@ -167,7 +120,7 @@ fn walk_and_embed_assets_ensure_no_recursive_frame() {
 }
 
 #[test]
-fn walk_and_embed_assets_no_css() {
+fn passing_no_css() {
     let html = "<link rel=\"stylesheet\" href=\"main.css\">\
                 <style>html{background-color: #000;}</style>\
                 <div style=\"display: none;\"></div>";
@@ -212,7 +165,7 @@ fn walk_and_embed_assets_no_css() {
 }
 
 #[test]
-fn walk_and_embed_assets_no_images() {
+fn passing_no_images() {
     let html = "<link rel=\"icon\" href=\"favicon.ico\">\
                 <div><img src=\"http://localhost/assets/mono_lisa.png\" /></div>";
     let dom = html::html_to_dom(&html);
@@ -260,7 +213,7 @@ fn walk_and_embed_assets_no_images() {
 }
 
 #[test]
-fn walk_and_embed_assets_no_body_background_images() {
+fn passing_no_body_background_images() {
     let html = "<body background=\"no/such/image.png\" background=\"no/such/image2.png\"></body>";
     let dom = html::html_to_dom(&html);
     let url = "http://localhost";
@@ -296,7 +249,7 @@ fn walk_and_embed_assets_no_body_background_images() {
 }
 
 #[test]
-fn walk_and_embed_assets_no_frames() {
+fn passing_no_frames() {
     let html = "<frameset><frame src=\"http://trackbook.com\"></frameset>";
     let dom = html::html_to_dom(&html);
     let url = "http://localhost";
@@ -331,7 +284,7 @@ fn walk_and_embed_assets_no_frames() {
 }
 
 #[test]
-fn walk_and_embed_assets_no_iframes() {
+fn passing_no_iframes() {
     let html = "<iframe src=\"http://trackbook.com\"></iframe>";
     let dom = html::html_to_dom(&html);
     let url = "http://localhost";
@@ -366,7 +319,7 @@ fn walk_and_embed_assets_no_iframes() {
 }
 
 #[test]
-fn walk_and_embed_assets_no_js() {
+fn passing_no_js() {
     let html = "<div onClick=\"void(0)\">\
                 <script src=\"http://localhost/assets/some.js\"></script>\
                 <script>alert(1)</script>\
@@ -406,7 +359,7 @@ fn walk_and_embed_assets_no_js() {
 }
 
 #[test]
-fn walk_and_embed_with_no_integrity() {
+fn passing_with_no_integrity() {
     let html = "<title>No integrity</title>\
                 <link integrity=\"sha384-...\" rel=\"something\"/>\
                 <script integrity=\"sha384-...\" src=\"some.js\"></script>";
@@ -443,183 +396,3 @@ fn walk_and_embed_with_no_integrity() {
          </html>"
     );
 }
-
-#[test]
-fn stringify_document() {
-    let html = "<div><script src=\"some.js\"></script></div>";
-    let dom = html::html_to_dom(&html);
-
-    let opt_no_css: bool = false;
-    let opt_no_frames: bool = false;
-    let opt_no_js: bool = false;
-    let opt_no_images: bool = false;
-    let opt_isolate: bool = false;
-
-    assert_eq!(
-        html::stringify_document(
-            &dom.document,
-            opt_no_css,
-            opt_no_frames,
-            opt_no_js,
-            opt_no_images,
-            opt_isolate,
-        ),
-        "<html><head></head><body><div><script src=\"some.js\"></script></div></body></html>"
-    );
-}
-
-#[test]
-fn stringify_document_isolate() {
-    let html = "<title>Isolated document</title>\
-                <link rel=\"something\" href=\"some.css\" />\
-                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
-                <div><script src=\"some.js\"></script></div>";
-    let dom = html::html_to_dom(&html);
-
-    let opt_no_css: bool = false;
-    let opt_no_frames: bool = false;
-    let opt_no_js: bool = false;
-    let opt_no_images: bool = false;
-    let opt_isolate: bool = true;
-
-    assert_eq!(
-        html::stringify_document(
-            &dom.document,
-            opt_no_css,
-            opt_no_frames,
-            opt_no_js,
-            opt_no_images,
-            opt_isolate,
-        ),
-        "<html>\
-            <head>\
-                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:;\"></meta>\
-                <title>Isolated document</title>\
-                <link rel=\"something\" href=\"some.css\">\
-                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
-            </head>\
-            <body>\
-                <div>\
-                    <script src=\"some.js\"></script>\
-                </div>\
-            </body>\
-         </html>"
-    );
-}
-
-#[test]
-fn stringify_document_no_css() {
-    let html = "<!doctype html>\
-                <title>Unstyled document</title>\
-                <link rel=\"stylesheet\" href=\"main.css\"/>\
-                <div style=\"display: none;\"></div>";
-    let dom = html::html_to_dom(&html);
-
-    let opt_no_css: bool = true;
-    let opt_no_frames: bool = false;
-    let opt_no_js: bool = false;
-    let opt_no_images: bool = false;
-    let opt_isolate: bool = false;
-
-    assert_eq!(
-        html::stringify_document(
-            &dom.document,
-            opt_no_css,
-            opt_no_frames,
-            opt_no_js,
-            opt_no_images,
-            opt_isolate,
-        ),
-        "<!DOCTYPE html>\
-         <html>\
-         <head>\
-         <meta http-equiv=\"Content-Security-Policy\" content=\"style-src 'none';\"></meta>\
-         <title>Unstyled document</title>\
-         <link rel=\"stylesheet\" href=\"main.css\">\
-         </head>\
-         <body><div style=\"display: none;\"></div></body>\
-         </html>"
-    );
-}
-
-#[test]
-fn stringify_document_no_frames() {
-    let html = "<!doctype html>\
-                <title>Frameless document</title>\
-                <link rel=\"something\"/>\
-                <div><script src=\"some.js\"></script></div>";
-    let dom = html::html_to_dom(&html);
-
-    let opt_no_css: bool = false;
-    let opt_no_frames: bool = true;
-    let opt_no_js: bool = false;
-    let opt_no_images: bool = false;
-    let opt_isolate: bool = false;
-
-    assert_eq!(
-        html::stringify_document(
-            &dom.document,
-            opt_no_css,
-            opt_no_frames,
-            opt_no_js,
-            opt_no_images,
-            opt_isolate,
-        ),
-        "<!DOCTYPE html>\
-            <html>\
-            <head>\
-            <meta http-equiv=\"Content-Security-Policy\" content=\"frame-src 'none';child-src 'none';\"></meta>\
-            <title>Frameless document</title>\
-            <link rel=\"something\">\
-            </head>\
-            <body><div><script src=\"some.js\"></script></div></body>\
-            </html>"
-    );
-}
-
-#[test]
-fn stringify_document_isolate_no_frames_no_js_no_css_no_images() {
-    let html = "<!doctype html>\
-                <title>no-frame no-css no-js no-image isolated document</title>\
-                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
-                <link rel=\"stylesheet\" href=\"some.css\">\
-                <div>\
-                <script src=\"some.js\"></script>\
-                <img style=\"width: 100%;\" src=\"some.png\" />\
-                <iframe src=\"some.html\"></iframe>\
-                </div>";
-    let dom = html::html_to_dom(&html);
-
-    let opt_isolate: bool = true;
-    let opt_no_css: bool = true;
-    let opt_no_frames: bool = true;
-    let opt_no_js: bool = true;
-    let opt_no_images: bool = true;
-
-    assert_eq!(
-        html::stringify_document(
-            &dom.document,
-            opt_no_css,
-            opt_no_frames,
-            opt_no_js,
-            opt_no_images,
-            opt_isolate,
-        ),
-        "<!DOCTYPE html>\
-            <html>\
-                <head>\
-                    <meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:; style-src 'none'; frame-src 'none';child-src 'none'; script-src 'none'; img-src data:;\"></meta>\
-                    <title>no-frame no-css no-js no-image isolated document</title>\
-                    <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
-                    <link rel=\"stylesheet\" href=\"some.css\">\
-                </head>\
-                <body>\
-                    <div>\
-                        <script src=\"some.js\"></script>\
-                        <img style=\"width: 100%;\" src=\"some.png\">\
-                        <iframe src=\"some.html\"></iframe>\
-                    </div>\
-                </body>\
-            </html>"
-    );
-}
diff --git a/src/tests/js.rs b/src/tests/js.rs
deleted file mode 100644
index 63cf76d..0000000
--- a/src/tests/js.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-use crate::js::attr_is_event_handler;
-
-#[test]
-fn attr_is_event_handler() {
-    // Passing
-    assert!(attr_is_event_handler("onBlur"));
-    assert!(attr_is_event_handler("onclick"));
-    assert!(attr_is_event_handler("onClick"));
-
-    // Failing
-    assert!(!attr_is_event_handler("href"));
-    assert!(!attr_is_event_handler(""));
-    assert!(!attr_is_event_handler("class"));
-}
diff --git a/src/tests/js/attr_is_event_handler.rs b/src/tests/js/attr_is_event_handler.rs
new file mode 100644
index 0000000..fbc2146
--- /dev/null
+++ b/src/tests/js/attr_is_event_handler.rs
@@ -0,0 +1,45 @@
+use crate::js;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_onblur_camelcase() {
+    assert!(js::attr_is_event_handler("onBlur"));
+}
+
+#[test]
+fn passing_onclick_lowercase() {
+    assert!(js::attr_is_event_handler("onclick"));
+}
+
+#[test]
+fn passing_onclick_camelcase() {
+    assert!(js::attr_is_event_handler("onClick"));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_href() {
+    assert!(!js::attr_is_event_handler("href"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!js::attr_is_event_handler(""));
+}
+
+#[test]
+fn failing_class() {
+    assert!(!js::attr_is_event_handler("class"));
+}
diff --git a/src/tests/js/mod.rs b/src/tests/js/mod.rs
new file mode 100644
index 0000000..46bcf24
--- /dev/null
+++ b/src/tests/js/mod.rs
@@ -0,0 +1 @@
+mod attr_is_event_handler;
diff --git a/src/tests/utils.rs b/src/tests/utils.rs
deleted file mode 100644
index fece56c..0000000
--- a/src/tests/utils.rs
+++ /dev/null
@@ -1,383 +0,0 @@
-use crate::utils;
-use reqwest::blocking::Client;
-use std::collections::HashMap;
-use std::env;
-use url::ParseError;
-
-#[test]
-fn data_to_data_url() {
-    let mime = "application/javascript";
-    let data = "var word = 'hello';\nalert(word);\n";
-    let datauri = utils::data_to_data_url(mime, data.as_bytes());
-    assert_eq!(
-        &datauri,
-        "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK"
-    );
-}
-
-#[test]
-fn detect_mimetype() {
-    // Image
-    assert_eq!(utils::detect_mimetype(b"GIF87a"), "image/gif");
-    assert_eq!(utils::detect_mimetype(b"GIF89a"), "image/gif");
-    assert_eq!(utils::detect_mimetype(b"\xFF\xD8\xFF"), "image/jpeg");
-    assert_eq!(
-        utils::detect_mimetype(b"\x89PNG\x0D\x0A\x1A\x0A"),
-        "image/png"
-    );
-    assert_eq!(utils::detect_mimetype(b"<?xml "), "image/svg+xml");
-    assert_eq!(utils::detect_mimetype(b"<svg "), "image/svg+xml");
-    assert_eq!(utils::detect_mimetype(b"RIFF....WEBPVP8 "), "image/webp");
-    assert_eq!(utils::detect_mimetype(b"\x00\x00\x01\x00"), "image/x-icon");
-
-    // Audio
-    assert_eq!(utils::detect_mimetype(b"ID3"), "audio/mpeg");
-    assert_eq!(utils::detect_mimetype(b"\xFF\x0E"), "audio/mpeg");
-    assert_eq!(utils::detect_mimetype(b"\xFF\x0F"), "audio/mpeg");
-    assert_eq!(utils::detect_mimetype(b"OggS"), "audio/ogg");
-    assert_eq!(utils::detect_mimetype(b"RIFF....WAVEfmt "), "audio/wav");
-    assert_eq!(utils::detect_mimetype(b"fLaC"), "audio/x-flac");
-
-    // Video
-    assert_eq!(utils::detect_mimetype(b"RIFF....AVI LIST"), "video/avi");
-    assert_eq!(utils::detect_mimetype(b"....ftyp"), "video/mp4");
-    assert_eq!(utils::detect_mimetype(b"\x00\x00\x01\x0B"), "video/mpeg");
-    assert_eq!(utils::detect_mimetype(b"....moov"), "video/quicktime");
-    assert_eq!(utils::detect_mimetype(b"\x1A\x45\xDF\xA3"), "video/webm");
-}
-
-#[test]
-fn url_has_protocol() {
-    // Passing
-    assert_eq!(
-        utils::url_has_protocol("mailto:somebody@somewhere.com?subject=hello"),
-        true
-    );
-    assert_eq!(utils::url_has_protocol("tel:5551234567"), true);
-    assert_eq!(
-        utils::url_has_protocol("ftp:user:password@some-ftp-server.com"),
-        true
-    );
-    assert_eq!(utils::url_has_protocol("javascript:void(0)"), true);
-    assert_eq!(utils::url_has_protocol("http://news.ycombinator.com"), true);
-    assert_eq!(utils::url_has_protocol("https://github.com"), true);
-    assert_eq!(
-        utils::url_has_protocol("MAILTO:somebody@somewhere.com?subject=hello"),
-        true
-    );
-
-    // Failing
-    assert_eq!(
-        utils::url_has_protocol("//some-hostname.com/some-file.html"),
-        false
-    );
-    assert_eq!(
-        utils::url_has_protocol("some-hostname.com/some-file.html"),
-        false
-    );
-    assert_eq!(utils::url_has_protocol("/some-file.html"), false);
-    assert_eq!(utils::url_has_protocol(""), false);
-}
-
-#[test]
-fn is_file_url() {
-    // Passing
-    assert!(utils::is_file_url(
-        "file:///home/user/Websites/my-website/index.html"
-    ));
-    assert!(utils::is_file_url(
-        "file:///C:/Documents%20and%20Settings/user/Websites/my-website/assets/images/logo.png"
-    ));
-    assert!(utils::is_file_url(
-        "file:\\\\\\home\\user\\Websites\\my-website\\index.html"
-    ));
-
-    // Failing
-    assert!(!utils::is_file_url("//kernel.org"));
-    assert!(!utils::is_file_url("./index.html"));
-    assert!(!utils::is_file_url("some-local-page.htm"));
-    assert!(!utils::is_file_url("https://1.2.3.4:80/www/index.html"));
-    assert!(!utils::is_file_url(
-        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
-    ));
-}
-
-#[test]
-fn is_http_url() {
-    // Passing
-    assert!(utils::is_http_url("https://www.rust-lang.org/"));
-    assert!(utils::is_http_url("http://kernel.org"));
-    assert!(utils::is_http_url("http:\\\\freebsd.org\\"));
-
-    // Failing
-    assert!(!utils::is_http_url("//kernel.org"));
-    assert!(!utils::is_http_url("./index.html"));
-    assert!(!utils::is_http_url("some-local-page.htm"));
-    assert!(!utils::is_http_url("ftp://1.2.3.4/www/index.html"));
-    assert!(!utils::is_http_url(
-        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
-    ));
-}
-
-#[test]
-fn resolve_url() -> Result<(), ParseError> {
-    let resolved_url = utils::resolve_url("https://www.kernel.org", "../category/signatures.html")?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.kernel.org/category/signatures.html"
-    );
-
-    let resolved_url = utils::resolve_url("https://www.kernel.org", "category/signatures.html")?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.kernel.org/category/signatures.html"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "saved_page.htm",
-        "https://www.kernel.org/category/signatures.html",
-    )?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.kernel.org/category/signatures.html"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "https://www.kernel.org",
-        "//www.kernel.org/theme/images/logos/tux.png",
-    )?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.kernel.org/theme/images/logos/tux.png"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "https://www.kernel.org",
-        "//another-host.org/theme/images/logos/tux.png",
-    )?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://another-host.org/theme/images/logos/tux.png"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "https://www.kernel.org/category/signatures.html",
-        "/theme/images/logos/tux.png",
-    )?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.kernel.org/theme/images/logos/tux.png"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "https://www.w3schools.com/html/html_iframe.asp",
-        "default.asp",
-    )?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.w3schools.com/html/default.asp"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
-        "https://www.kernel.org/category/signatures.html",
-    )?;
-    assert_eq!(
-        resolved_url.as_str(),
-        "https://www.kernel.org/category/signatures.html"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
-        "//www.w3schools.com/html/html_iframe.asp",
-    )
-    .unwrap_or(str!());
-    assert_eq!(resolved_url.as_str(), "");
-
-    let resolved_url = utils::resolve_url(
-        "file:///home/user/Websites/my-website/index.html",
-        "assets/images/logo.png",
-    )
-    .unwrap_or(str!());
-    assert_eq!(
-        resolved_url.as_str(),
-        "file:///home/user/Websites/my-website/assets/images/logo.png"
-    );
-
-    let resolved_url = utils::resolve_url(
-        "file:\\\\\\home\\user\\Websites\\my-website\\index.html",
-        "assets\\images\\logo.png",
-    )
-    .unwrap_or(str!());
-    assert_eq!(
-        resolved_url.as_str(),
-        "file:///home/user/Websites/my-website/assets/images/logo.png"
-    );
-
-    Ok(())
-}
-
-#[test]
-fn is_data_url() {
-    // Passing
-    assert!(utils::is_data_url(
-        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
-    ));
-
-    // Failing
-    assert!(!utils::is_data_url("https://kernel.org"));
-    assert!(!utils::is_data_url("//kernel.org"));
-    assert!(!utils::is_data_url(""));
-}
-
-#[test]
-fn clean_url() {
-    assert_eq!(
-        utils::clean_url("https://somewhere.com/font.eot#iefix"),
-        "https://somewhere.com/font.eot"
-    );
-    assert_eq!(
-        utils::clean_url("https://somewhere.com/font.eot#"),
-        "https://somewhere.com/font.eot"
-    );
-    assert_eq!(
-        utils::clean_url("https://somewhere.com/font.eot?#"),
-        "https://somewhere.com/font.eot"
-    );
-}
-
-#[test]
-fn data_url_to_text() {
-    assert_eq!(
-        utils::data_url_to_text("data:text/html;base64,V29yayBleHBhbmRzIHNvIGFzIHRvIGZpbGwgdGhlIHRpbWUgYXZhaWxhYmxlIGZvciBpdHMgY29tcGxldGlvbg=="),
-        "Work expands so as to fill the time available for its completion"
-    );
-
-    assert_eq!(
-        utils::data_url_to_text(
-            "data:text/html;utf8,Work expands so as to fill the time available for its completion"
-        ),
-        "Work expands so as to fill the time available for its completion"
-    );
-
-    assert_eq!(
-        utils::data_url_to_text(
-            "data:text/html,Work expands so as to fill the time available for its completion"
-        ),
-        "Work expands so as to fill the time available for its completion"
-    );
-
-    assert_eq!(
-        utils::data_url_to_text(
-            " data:text/html;charset=utf-8,Work expands so as to fill the time available for its completion "
-        ),
-        "Work expands so as to fill the time available for its completion"
-    );
-}
-
-#[test]
-fn decode_url() {
-    assert_eq!(
-        utils::decode_url(str!(
-            "%E6%A4%9C%E3%83%92%E3%83%A0%E8%A7%A3%E5%A1%97%E3%82%83%E3%83%83%20%3D%20%E3%82%B5"
-        )),
-        "検ヒム解塗ゃッ = サ"
-    );
-
-    assert_eq!(utils::decode_url(str!("%20 %20")), "   ");
-}
-
-#[test]
-fn retrieve_asset() {
-    let cache = &mut HashMap::new();
-    let client = Client::new();
-
-    let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
-
-    // If both source and target are data URLs,
-    // ensure the result contains target data URL
-    let (data, final_url) = utils::retrieve_asset(
-        cache,
-        &client,
-        "data:text/html;base64,SoUrCe",
-        "data:text/html;base64,TaRgEt",
-        true,
-        "",
-        false,
-    )
-    .unwrap();
-    assert_eq!(&data, "data:text/html;base64,TaRgEt");
-    assert_eq!(&final_url, "data:text/html;base64,TaRgEt");
-
-    // Media type parameter should not influence data URLs
-    let (data, final_url) = utils::retrieve_asset(
-        cache,
-        &client,
-        "data:text/html;base64,SoUrCe",
-        "data:text/html;base64,TaRgEt",
-        true,
-        "image/png",
-        false,
-    )
-    .unwrap();
-    assert_eq!(&data, "data:text/html;base64,TaRgEt");
-    assert_eq!(&final_url, "data:text/html;base64,TaRgEt");
-
-    // Inclusion of local assets from data URL sources should not be allowed
-    let (data, final_url) = utils::retrieve_asset(
-        cache,
-        &client,
-        "data:text/html;base64,SoUrCe",
-        "file:///etc/passwd",
-        true,
-        "",
-        false,
-    )
-    .unwrap();
-    assert_eq!(&data, "");
-    assert_eq!(&final_url, "");
-
-    // Inclusion of local assets from remote sources should not be allowed
-    let (data, final_url) = utils::retrieve_asset(
-        cache,
-        &client,
-        "https://kernel.org/",
-        "file:///etc/passwd",
-        true,
-        "",
-        false,
-    )
-    .unwrap();
-    assert_eq!(&data, "");
-    assert_eq!(&final_url, "");
-
-    // Inclusion of local assets from local sources should be allowed
-    let cwd = env::current_dir().unwrap();
-    let (data, final_url) = utils::retrieve_asset(
-        cache,
-        &client,
-        &format!(
-            "{file}{cwd}/src/tests/data/local-file.html",
-            file = file_url_protocol,
-            cwd = cwd.to_str().unwrap()
-        ),
-        &format!(
-            "{file}{cwd}/src/tests/data/local-script.js",
-            file = file_url_protocol,
-            cwd = cwd.to_str().unwrap()
-        ),
-        true,
-        "application/javascript",
-        false,
-    )
-    .unwrap();
-    assert_eq!(&data, "data:application/javascript;base64,ZG9jdW1lbnQuYm9keS5zdHlsZS5iYWNrZ3JvdW5kQ29sb3IgPSAiZ3JlZW4iOwpkb2N1bWVudC5ib2R5LnN0eWxlLmNvbG9yID0gInJlZCI7Cg==");
-    assert_eq!(
-        &final_url,
-        &format!(
-            "{file}{cwd}/src/tests/data/local-script.js",
-            file = file_url_protocol,
-            cwd = cwd.to_str().unwrap()
-        )
-    );
-}
diff --git a/src/tests/utils/clean_url.rs b/src/tests/utils/clean_url.rs
new file mode 100644
index 0000000..7e794be
--- /dev/null
+++ b/src/tests/utils/clean_url.rs
@@ -0,0 +1,32 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_removes_fragment() {
+    assert_eq!(
+        utils::clean_url("https://somewhere.com/font.eot#iefix"),
+        "https://somewhere.com/font.eot"
+    );
+}
+
+#[test]
+fn passing_removes_empty_fragment() {
+    assert_eq!(
+        utils::clean_url("https://somewhere.com/font.eot#"),
+        "https://somewhere.com/font.eot"
+    );
+}
+
+#[test]
+fn passing_removes_empty_query_and_empty_fragment() {
+    assert_eq!(
+        utils::clean_url("https://somewhere.com/font.eot?#"),
+        "https://somewhere.com/font.eot"
+    );
+}
diff --git a/src/tests/utils/data_to_data_url.rs b/src/tests/utils/data_to_data_url.rs
new file mode 100644
index 0000000..bccdf77
--- /dev/null
+++ b/src/tests/utils/data_to_data_url.rs
@@ -0,0 +1,20 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_encode_string_with_specific_media_type() {
+    let mime = "application/javascript";
+    let data = "var word = 'hello';\nalert(word);\n";
+    let data_url = utils::data_to_data_url(mime, data.as_bytes());
+
+    assert_eq!(
+        &data_url,
+        "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK"
+    );
+}
diff --git a/src/tests/utils/data_url_to_text.rs b/src/tests/utils/data_url_to_text.rs
new file mode 100644
index 0000000..b7d50b2
--- /dev/null
+++ b/src/tests/utils/data_url_to_text.rs
@@ -0,0 +1,58 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_parse_text_html_base64() {
+    assert_eq!(
+        utils::data_url_to_text("data:text/html;base64,V29yayBleHBhbmRzIHNvIGFzIHRvIGZpbGwgdGhlIHRpbWUgYXZhaWxhYmxlIGZvciBpdHMgY29tcGxldGlvbg=="),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+#[test]
+fn passing_parse_text_html_utf8() {
+    assert_eq!(
+        utils::data_url_to_text(
+            "data:text/html;utf8,Work expands so as to fill the time available for its completion"
+        ),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+#[test]
+fn passing_parse_text_html_plaintext() {
+    assert_eq!(
+        utils::data_url_to_text(
+            "data:text/html,Work expands so as to fill the time available for its completion"
+        ),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+#[test]
+fn passing_parse_text_html_charset_utf_8_between_two_whitespaces() {
+    assert_eq!(
+        utils::data_url_to_text(
+            " data:text/html;charset=utf-8,Work expands so as to fill the time available for its completion "
+        ),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_just_word_data() {
+    assert_eq!(utils::data_url_to_text("data"), "");
+}
diff --git a/src/tests/utils/decode_url.rs b/src/tests/utils/decode_url.rs
new file mode 100644
index 0000000..e839ac1
--- /dev/null
+++ b/src/tests/utils/decode_url.rs
@@ -0,0 +1,23 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_decode_unicode_characters() {
+    assert_eq!(
+        utils::decode_url(str!(
+            "%E6%A4%9C%E3%83%92%E3%83%A0%E8%A7%A3%E5%A1%97%E3%82%83%E3%83%83%20%3D%20%E3%82%B5"
+        )),
+        "検ヒム解塗ゃッ = サ"
+    );
+}
+
+#[test]
+fn passing_decode_whitespaces() {
+    assert_eq!(utils::decode_url(str!("%20 %20")), "   ");
+}
diff --git a/src/tests/utils/detect_media_type.rs b/src/tests/utils/detect_media_type.rs
new file mode 100644
index 0000000..99dc51f
--- /dev/null
+++ b/src/tests/utils/detect_media_type.rs
@@ -0,0 +1,57 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_image_media_types() {
+    assert_eq!(utils::detect_media_type(b"GIF87a"), "image/gif");
+    assert_eq!(utils::detect_media_type(b"GIF89a"), "image/gif");
+    assert_eq!(utils::detect_media_type(b"\xFF\xD8\xFF"), "image/jpeg");
+    assert_eq!(
+        utils::detect_media_type(b"\x89PNG\x0D\x0A\x1A\x0A"),
+        "image/png"
+    );
+    assert_eq!(utils::detect_media_type(b"<?xml "), "image/svg+xml");
+    assert_eq!(utils::detect_media_type(b"<svg "), "image/svg+xml");
+    assert_eq!(utils::detect_media_type(b"RIFF....WEBPVP8 "), "image/webp");
+    assert_eq!(
+        utils::detect_media_type(b"\x00\x00\x01\x00"),
+        "image/x-icon"
+    );
+}
+
+#[test]
+fn passing_audio_media_types() {
+    assert_eq!(utils::detect_media_type(b"ID3"), "audio/mpeg");
+    assert_eq!(utils::detect_media_type(b"\xFF\x0E"), "audio/mpeg");
+    assert_eq!(utils::detect_media_type(b"\xFF\x0F"), "audio/mpeg");
+    assert_eq!(utils::detect_media_type(b"OggS"), "audio/ogg");
+    assert_eq!(utils::detect_media_type(b"RIFF....WAVEfmt "), "audio/wav");
+    assert_eq!(utils::detect_media_type(b"fLaC"), "audio/x-flac");
+}
+
+#[test]
+fn passing_video_media_types() {
+    assert_eq!(utils::detect_media_type(b"RIFF....AVI LIST"), "video/avi");
+    assert_eq!(utils::detect_media_type(b"....ftyp"), "video/mp4");
+    assert_eq!(utils::detect_media_type(b"\x00\x00\x01\x0B"), "video/mpeg");
+    assert_eq!(utils::detect_media_type(b"....moov"), "video/quicktime");
+    assert_eq!(utils::detect_media_type(b"\x1A\x45\xDF\xA3"), "video/webm");
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_unknown_media_type() {
+    assert_eq!(utils::detect_media_type(b"abcdef0123456789"), "");
+}
diff --git a/src/tests/utils/is_data_url.rs b/src/tests/utils/is_data_url.rs
new file mode 100644
index 0000000..0db0c8c
--- /dev/null
+++ b/src/tests/utils/is_data_url.rs
@@ -0,0 +1,44 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_data_url_text_html() {
+    assert!(utils::is_data_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
+
+#[test]
+fn passing_data_url_no_media_type() {
+    assert!(utils::is_data_url(
+        "data:;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_https_url() {
+    assert!(!utils::is_data_url("https://kernel.org"));
+}
+
+#[test]
+fn failing_no_protocol_url() {
+    assert!(!utils::is_data_url("//kernel.org"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!utils::is_data_url(""));
+}
diff --git a/src/tests/utils/is_file_url.rs b/src/tests/utils/is_file_url.rs
new file mode 100644
index 0000000..578178b
--- /dev/null
+++ b/src/tests/utils/is_file_url.rs
@@ -0,0 +1,75 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_unix_file_url() {
+    assert!(utils::is_file_url(
+        "file:///home/user/Websites/my-website/index.html"
+    ));
+}
+
+#[test]
+fn passing_windows_file_url() {
+    assert!(utils::is_file_url(
+        "file:///C:/Documents%20and%20Settings/user/Websites/my-website/assets/images/logo.png"
+    ));
+}
+
+#[test]
+fn passing_unix_url_with_backslashes() {
+    assert!(utils::is_file_url(
+        "file:\\\\\\home\\user\\Websites\\my-website\\index.html"
+    ));
+}
+
+#[test]
+fn passing_windows_file_url_with_backslashes() {
+    assert!(utils::is_file_url(
+        "file:\\\\\\C:\\Documents%20and%20Settings\\user\\Websites\\my-website\\assets\\images\\logo.png"
+    ));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_url_with_no_protocl() {
+    assert!(!utils::is_file_url("//kernel.org"));
+}
+
+#[test]
+fn failing_dot_slash_filename() {
+    assert!(!utils::is_file_url("./index.html"));
+}
+
+#[test]
+fn failing_just_filename() {
+    assert!(!utils::is_file_url("some-local-page.htm"));
+}
+
+#[test]
+fn failing_https_ip_port_url() {
+    assert!(!utils::is_file_url("https://1.2.3.4:80/www/index.html"));
+}
+
+#[test]
+fn failing_data_url() {
+    assert!(!utils::is_file_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
+
+#[test]
+fn failing_just_word_file() {
+    assert!(!utils::is_file_url("file"));
+}
diff --git a/src/tests/utils/is_http_url.rs b/src/tests/utils/is_http_url.rs
new file mode 100644
index 0000000..9656dc2
--- /dev/null
+++ b/src/tests/utils/is_http_url.rs
@@ -0,0 +1,57 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_http_url() {
+    assert!(utils::is_http_url("http://kernel.org"));
+}
+
+#[test]
+fn passing_https_url() {
+    assert!(utils::is_http_url("https://www.rust-lang.org/"));
+}
+
+#[test]
+fn passing_http_url_with_backslashes() {
+    assert!(utils::is_http_url("http:\\\\freebsd.org\\"));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_url_with_no_protocol() {
+    assert!(!utils::is_http_url("//kernel.org"));
+}
+
+#[test]
+fn failing_dot_slash_filename() {
+    assert!(!utils::is_http_url("./index.html"));
+}
+
+#[test]
+fn failing_just_filename() {
+    assert!(!utils::is_http_url("some-local-page.htm"));
+}
+
+#[test]
+fn failing_https_ip_port_url() {
+    assert!(!utils::is_http_url("ftp://1.2.3.4/www/index.html"));
+}
+
+#[test]
+fn failing_data_url() {
+    assert!(!utils::is_http_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
diff --git a/src/tests/utils/mod.rs b/src/tests/utils/mod.rs
new file mode 100644
index 0000000..c11f975
--- /dev/null
+++ b/src/tests/utils/mod.rs
@@ -0,0 +1,11 @@
+mod clean_url;
+mod data_to_data_url;
+mod data_url_to_text;
+mod decode_url;
+mod detect_media_type;
+mod is_data_url;
+mod is_file_url;
+mod is_http_url;
+mod resolve_url;
+mod retrieve_asset;
+mod url_has_protocol;
diff --git a/src/tests/utils/resolve_url.rs b/src/tests/utils/resolve_url.rs
new file mode 100644
index 0000000..ab62f8f
--- /dev/null
+++ b/src/tests/utils/resolve_url.rs
@@ -0,0 +1,177 @@
+use crate::utils;
+use url::ParseError;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_from_https_to_level_up_relative() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url("https://www.kernel.org", "../category/signatures.html")?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/category/signatures.html"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_just_filename_to_full_https_url() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "saved_page.htm",
+        "https://www.kernel.org/category/signatures.html",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/category/signatures.html"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_url_to_url_with_no_protocol() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.kernel.org",
+        "//www.kernel.org/theme/images/logos/tux.png",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/theme/images/logos/tux.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_url_to_url_with_no_protocol_and_on_different_hostname(
+) -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.kernel.org",
+        "//another-host.org/theme/images/logos/tux.png",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://another-host.org/theme/images/logos/tux.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_url_to_relative_root_path() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.kernel.org/category/signatures.html",
+        "/theme/images/logos/tux.png",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/theme/images/logos/tux.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_to_just_filename() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.w3schools.com/html/html_iframe.asp",
+        "default.asp",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.w3schools.com/html/default.asp"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_data_url_to_https() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "https://www.kernel.org/category/signatures.html",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/category/signatures.html"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_file_url_to_relative_path() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "file:///home/user/Websites/my-website/index.html",
+        "assets/images/logo.png",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "file:///home/user/Websites/my-website/assets/images/logo.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_file_url_to_relative_path_with_backslashes() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "file:\\\\\\home\\user\\Websites\\my-website\\index.html",
+        "assets\\images\\logo.png",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "file:///home/user/Websites/my-website/assets/images/logo.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_data_url_to_file_url() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "file:///etc/passwd",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(resolved_url.as_str(), "file:///etc/passwd");
+
+    Ok(())
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_from_data_url_to_url_with_no_protocol() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "//www.w3schools.com/html/html_iframe.asp",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(resolved_url.as_str(), "");
+
+    Ok(())
+}
diff --git a/src/tests/utils/retrieve_asset.rs b/src/tests/utils/retrieve_asset.rs
new file mode 100644
index 0000000..bfa4dc2
--- /dev/null
+++ b/src/tests/utils/retrieve_asset.rs
@@ -0,0 +1,137 @@
+use crate::utils;
+use reqwest::blocking::Client;
+use std::collections::HashMap;
+use std::env;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_read_data_url() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // If both source and target are data URLs,
+    // ensure the result contains target data URL
+    let (retrieved_data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "data:text/html;base64,SoUrCe",
+        "data:text/html;base64,TaRgEt",
+        true,
+        "",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&retrieved_data, "data:text/html;base64,TaRgEt");
+    assert_eq!(&final_url, "data:text/html;base64,TaRgEt");
+}
+
+#[test]
+fn passing_read_data_url_ignore_suggested_media_type() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // Media type parameter should not influence data URLs
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "data:text/html;base64,SoUrCe",
+        "data:text/html;base64,TaRgEt",
+        true,
+        "image/png",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "data:text/html;base64,TaRgEt");
+    assert_eq!(&final_url, "data:text/html;base64,TaRgEt");
+}
+
+#[test]
+fn passing_read_local_file_with_file_url_parent() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
+
+    // Inclusion of local assets from local sources should be allowed
+    let cwd = env::current_dir().unwrap();
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        &format!(
+            "{file}{cwd}/src/tests/data/local-file.html",
+            file = file_url_protocol,
+            cwd = cwd.to_str().unwrap()
+        ),
+        &format!(
+            "{file}{cwd}/src/tests/data/local-script.js",
+            file = file_url_protocol,
+            cwd = cwd.to_str().unwrap()
+        ),
+        true,
+        "application/javascript",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "data:application/javascript;base64,ZG9jdW1lbnQuYm9keS5zdHlsZS5iYWNrZ3JvdW5kQ29sb3IgPSAiZ3JlZW4iOwpkb2N1bWVudC5ib2R5LnN0eWxlLmNvbG9yID0gInJlZCI7Cg==");
+    assert_eq!(
+        &final_url,
+        &format!(
+            "{file}{cwd}/src/tests/data/local-script.js",
+            file = file_url_protocol,
+            cwd = cwd.to_str().unwrap()
+        )
+    );
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_read_local_file_with_data_url_parent() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // Inclusion of local assets from data URL sources should not be allowed
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "data:text/html;base64,SoUrCe",
+        "file:///etc/passwd",
+        true,
+        "",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "");
+    assert_eq!(&final_url, "");
+}
+
+#[test]
+fn failing_read_local_file_with_https_parent() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // Inclusion of local assets from remote sources should not be allowed
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "https://kernel.org/",
+        "file:///etc/passwd",
+        true,
+        "",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "");
+    assert_eq!(&final_url, "");
+}
diff --git a/src/tests/utils/url_has_protocol.rs b/src/tests/utils/url_has_protocol.rs
new file mode 100644
index 0000000..1c6e213
--- /dev/null
+++ b/src/tests/utils/url_has_protocol.rs
@@ -0,0 +1,83 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_mailto() {
+    assert!(utils::url_has_protocol(
+        "mailto:somebody@somewhere.com?subject=hello"
+    ));
+}
+
+#[test]
+fn passing_tel() {
+    assert!(utils::url_has_protocol("tel:5551234567"));
+}
+
+#[test]
+fn passing_ftp_no_slashes() {
+    assert!(utils::url_has_protocol("ftp:some-ftp-server.com"));
+}
+
+#[test]
+fn passing_ftp_with_credentials() {
+    assert!(utils::url_has_protocol(
+        "ftp://user:password@some-ftp-server.com"
+    ));
+}
+
+#[test]
+fn passing_javascript() {
+    assert!(utils::url_has_protocol("javascript:void(0)"));
+}
+
+#[test]
+fn passing_http() {
+    assert!(utils::url_has_protocol("http://news.ycombinator.com"));
+}
+
+#[test]
+fn passing_https() {
+    assert!(utils::url_has_protocol("https://github.com"));
+}
+
+#[test]
+fn passing_mailto_uppercase() {
+    assert!(utils::url_has_protocol(
+        "MAILTO:somebody@somewhere.com?subject=hello"
+    ));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_url_with_no_protocol() {
+    assert!(!utils::url_has_protocol(
+        "//some-hostname.com/some-file.html"
+    ));
+}
+
+#[test]
+fn failing_relative_path() {
+    assert!(!utils::url_has_protocol("some-hostname.com/some-file.html"));
+}
+
+#[test]
+fn failing_relative_to_root_path() {
+    assert!(!utils::url_has_protocol("/some-file.html"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!utils::url_has_protocol(""));
+}
diff --git a/src/utils.rs b/src/utils.rs
index fb38116..13ba70f 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -68,15 +68,15 @@ const MAGIC: [[&[u8]; 2]; 19] = [
 ];
 
 pub fn data_to_data_url(mime: &str, data: &[u8]) -> String {
-    let mimetype = if mime.is_empty() {
-        detect_mimetype(data)
+    let media_type = if mime.is_empty() {
+        detect_media_type(data)
     } else {
         mime.to_string()
     };
-    format!("data:{};base64,{}", mimetype, base64::encode(data))
+    format!("data:{};base64,{}", media_type, base64::encode(data))
 }
 
-pub fn detect_mimetype(data: &[u8]) -> String {
+pub fn detect_media_type(data: &[u8]) -> String {
     for item in MAGIC.iter() {
         if data.starts_with(item[0]) {
             return String::from_utf8(item[1].to_vec()).unwrap();
@@ -356,7 +356,7 @@ pub fn retrieve_asset(
                 response.copy_to(&mut data)?;
 
                 // Attempt to obtain MIME type by reading the Content-Type header
-                let mimetype = if mime == "" {
+                let media_type = if mime == "" {
                     response
                         .headers()
                         .get(CONTENT_TYPE)
@@ -365,7 +365,7 @@ pub fn retrieve_asset(
                 } else {
                     mime
                 };
-                let data_url = data_to_data_url(&mimetype, &data);
+                let data_url = data_to_data_url(&media_type, &data);
                 // Add to cache
                 cache.insert(new_cache_key, data_url.clone());
                 Ok((data_url, res_url))