add basic tests and travis config

.hastest.bats

@@ -0,0 +1,19 @@
+#!/usr/bin/env bats
+
+@test "works with single command check" {
+    result=$(bash has node)
+
+   [[ $result == *"✔ node"* ]]
+}
+
+@test "safely tells about tools not configured" {
+    result=$(bash has something-missing)
+
+   [[ $result == *"✘ something-missing not understood"* ]]
+}
+
+@test "env lets override safety check" {
+    result=$(HAS_ALLOW_UNSAFE=y bash has something-missing)
+
+   [[ $result == *"✘ something-missing"* ]]
+}

.travis.yml

@@ -0,0 +1,9 @@
+language: bash
+before_install:
+  - sudo add-apt-repository ppa:duggan/bats --yes
+  - sudo apt-get update -qq
+  - sudo apt-get install -qq bats
+install:
+  - sudo apt-get install -qq bc
+script:
+  - bats .hastest.bats