Ensure languages are sorted

lib/linguist/languages.yml

@@ -139,6 +139,13 @@ C-ObjDump:
   extensions:
   - .c-objdump
 
+CMake:
+  extensions:
+  - .cmake
+  - .cmake.in
+  filenames:
+  - CMakeLists.txt
+
 CSS:
   extensions:
   - .css
@@ -154,13 +161,6 @@ Clojure:
   - .clj
   - .cljs
 
-CMake:
-  extensions:
-  - .cmake
-  - .cmake.in
-  filenames:
-  - CMakeLists.txt
-
 CoffeeScript:
   type: programming
   extensions:

test/test_pedantic.rb

@@ -0,0 +1,29 @@
+require 'test/unit'
+
+class TestPedantic < Test::Unit::TestCase
+  Lib = File.expand_path("../../lib/linguist", __FILE__)
+
+  def file(name)
+    File.read(File.join(Lib, name))
+  end
+
+  def test_language_names_are_sorted
+    languages = []
+    file("languages.yml").lines.each do |line|
+      if line =~ /^(\w+):$/
+        languages << $1
+      end
+    end
+    assert_sorted languages
+  end
+
+  def assert_sorted(list)
+    previous = nil
+    list.each do |item|
+      if previous && previous > item
+        flunk "#{previous} should come after #{item}"
+      end
+      previous = item
+    end
+  end
+end