diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 1edb0a6..c1207fb 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -3,6 +3,12 @@
 	<testsuites>
 		<testsuite name="ParsedownTests">
 			<file>tests/ParsedownTest.php</file>
+			<file>tests/CommonMarkTest.php</file>			
 		</testsuite>
 	</testsuites>
+	<groups>
+		<exclude>
+			<group>update</group>
+		</exclude>
+	</groups>
 </phpunit>
diff --git a/tests/CommonMarkTest.php b/tests/CommonMarkTest.php
new file mode 100644
index 0000000..67a41f2
--- /dev/null
+++ b/tests/CommonMarkTest.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace Erusev\Parsedown\Tests;
+
+/**
+ * Test Parsedown against cached expect-to-pass CommonMark spec examples
+ *
+ * This test suite runs tests the same way as `test/CommonMarkTestWeak.php`,
+ * but uses a cached set of CommonMark spec examples in `test/commonmark/`.
+ * It is executed along with Parsedown's default test suite and runs various
+ * CommonMark spec examples, which are expected to pass. If they don't pass,
+ * the Parsedown build fails. The intention of this test suite is to make sure,
+ * that previously passed CommonMark spec examples don't fail due to unwanted
+ * side-effects of code changes.
+ *
+ * You can re-create the `test/commonmark/` directory by executing the PHPUnit
+ * group `update`. The test suite will then run `test/CommonMarkTestWeak.php`
+ * and create files with the Markdown source and the resulting HTML markup of
+ * all passed tests. The command to execute looks like the following:
+ *
+ *     $ phpunit --group update
+ *
+ * @link http://commonmark.org/ CommonMark
+ */
+class CommonMarkTest extends CommonMarkTestWeak
+{
+    /**
+     * @return array
+     */
+    public function data()
+    {
+        $data = [];
+
+        $dir = static::getDataDir();
+        $files = @\scandir($dir);
+        if (!empty($files)) {
+            foreach ($files as $file) {
+                if (($file === '.') || ($file === '..')) {
+                    continue;
+                }
+
+                if (\substr($file, -3) === '.md') {
+                    $testName = \substr($file, 0, -3);
+                    if (\file_exists($dir . $testName . '.html')) {
+                        \preg_match('/^(\d+)-(.*)$/', $testName, $matches);
+                        $id = isset($matches[1]) ? \intval($matches[1]) : 0;
+                        $section = isset($matches[2]) ? \preg_replace('/_+/', ' ', $matches[2]) : '';
+
+                        $markdown = \file_get_contents($dir . $testName . '.md');
+                        $expectedHtml = \file_get_contents($dir . $testName . '.html');
+
+                        $data[] = [
+                            'id' => $id,
+                            'section' => $section,
+                            'markdown' => $markdown,
+                            'expectedHtml' => $expectedHtml
+                        ];
+                    }
+                }
+            }
+        } else {
+            $this->fail('The CommonMark cache folder ' . $dir . ' is empty or not readable.');
+        }
+
+        return $data;
+    }
+
+    /**
+     * @group update
+     * @dataProvider dataUpdate
+     * @param $id
+     * @param $section
+     * @param $markdown
+     * @param $expectedHtml
+     */
+    public function testUpdateDatabase($id, $section, $markdown, $expectedHtml)
+    {
+        parent::testExample($id, $section, $markdown, $expectedHtml);
+
+        // you can only get here when the test passes
+        $dir = static::getDataDir(true);
+        $basename = $id . '-' . \preg_replace('/[^\w-.]/', '_', $section);
+        \file_put_contents($dir . $basename . '.md', $markdown);
+        \file_put_contents($dir . $basename . '.html', $expectedHtml);
+    }
+
+    /**
+     * @return array
+     */
+    public function dataUpdate()
+    {
+        return parent::data();
+    }
+
+    public static function getDataDir($mkdir = false)
+    {
+        $dir = __DIR__ . '/commonmark/';
+
+        if ($mkdir) {
+            if (!\file_exists($dir)) {
+                @\mkdir($dir);
+            }
+            if (!\is_dir($dir)) {
+                static::fail('Unable to create CommonMark cache folder ' . $dir . '.');
+            }
+        }
+
+        return $dir;
+    }
+}