Add tests for Sprockets::Environment

Rakefile

@@ -4,6 +4,6 @@ task :default => :test
 
 Rake::TestTask.new do |t|
   t.libs << "test"
-  t.test_files = FileList["test/*_test.rb"]
+  t.test_files = FileList["test/test_*.rb"]
   t.verbose = true
 end

lib/sprockets/environment.rb

@@ -3,20 +3,13 @@ class Environment
     attr_reader :root, :load_path
 
     def initialize(root, load_path = [])
-      @root = pathname_from(File.expand_path(root))
-      @load_path = [@root]
-
-      load_path.each do |location|
+      @load_path = [@root = Pathname.new(self, root)]
+
+      load_path.reverse_each do |location|
         register_load_location(location)
       end
     end
 
-    def absolute_location_from(location)
-      location = location.to_s
-      location = File.join(root.absolute_location, location) unless location[/^\//]
-      File.expand_path(location)
-    end
-
     def pathname_from(location)
       Pathname.new(self, absolute_location_from(location))
     end
@@ -31,5 +24,12 @@ def register_load_location(location)
     def find(location)
       load_path.map { |pathname| pathname.find(location) }.compact.first
     end
+
+    protected
+      def absolute_location_from(location)
+        location = location.to_s
+        location = File.join(root.absolute_location, location) unless location[/^\//]
+        File.expand_path(location)
+      end
   end
 end

test/fixtures/src/foo/foo.js

@@ -0,0 +1 @@
+var FooFoo = { };

test/test_environment.rb

@@ -0,0 +1,66 @@
+require "test_helper"
+
+class EnvironmentTest < Test::Unit::TestCase
+  def test_load_path_locations_become_pathnames_for_absolute_locations_from_the_root
+    environment = Sprockets::Environment.new("/root", ["/a", "b"])
+    assert_load_path_equals ["/a", "/root/b", "/root"], environment
+  end
+
+  def test_pathname_from_for_location_with_leading_slash_should_return_a_pathname_with_the_location_unchanged
+    environment = Sprockets::Environment.new("/root")
+    assert_absolute_location "/a", environment.pathname_from("/a")
+  end
+
+  def test_pathname_from_for_relative_location_should_return_a_pathname_for_the_expanded_absolute_location_from_root
+    environment = Sprockets::Environment.new("/root")
+    assert_absolute_location "/root/a", environment.pathname_from("a")
+    assert_absolute_location "/root/a", environment.pathname_from("./a")
+    assert_absolute_location "/a", environment.pathname_from("../a")
+  end
+
+  def test_register_load_location_should_unshift_the_location_onto_the_load_path
+    environment = Sprockets::Environment.new("/root")
+    environment.register_load_location("a")
+    assert_load_path_equals ["/root/a", "/root"], environment
+    environment.register_load_location("b")
+    assert_load_path_equals ["/root/b", "/root/a", "/root"], environment
+  end
+
+  def test_register_load_location_should_remove_already_existing_locations_before_unshifting
+    environment = Sprockets::Environment.new("/root")
+    environment.register_load_location("a")
+    environment.register_load_location("b")
+    assert_load_path_equals ["/root/b", "/root/a", "/root"], environment
+    environment.register_load_location("a")
+    assert_load_path_equals ["/root/a", "/root/b", "/root"], environment
+  end
+
+  def test_find_should_return_the_first_matching_pathname_in_the_load_path
+    environment = environment_for_fixtures
+    first_pathname = environment.find("foo.js")
+    assert_absolute_location_ends_with "src/foo.js", first_pathname
+
+    environment.register_load_location(File.join(FIXTURES_PATH, "src", "foo"))
+    second_pathname = environment.find("foo.js")
+    assert_not_equal first_pathname, second_pathname
+    assert_absolute_location_ends_with "foo/foo.js", second_pathname
+  end
+
+  def test_find_should_return_nil_when_no_matching_source_file_is_found
+    environment = environment_for_fixtures
+    assert_nil environment.find("nonexistent.js")
+  end
+
+  protected
+    def assert_absolute_location(location, pathname)
+      assert_equal location, pathname.absolute_location
+    end
+
+    def assert_load_path_equals(load_path_absolute_locations, environment)
+      assert load_path_absolute_locations.zip(environment.load_path).map { |location, pathname| location == pathname.absolute_location }.all?
+    end
+
+    def assert_absolute_location_ends_with(location_ending, pathname)
+      assert pathname.absolute_location[/#{Regexp.escape(location_ending)}$/]
+    end
+end

test/test_helper.rb

@@ -2,5 +2,14 @@
 require "test/unit"
 
 class Test::Unit::TestCase
-  FIXTURES_PATH = File.expand_path(File.join(File.dirname(__FILE__), "fixtures"))
+  FIXTURES_PATH = File.expand_path(File.join(File.dirname(__FILE__), "fixtures")) unless defined?(FIXTURES_PATH)
+
+  protected
+    def environment_for_fixtures
+      Sprockets::Environment.new(FIXTURES_PATH, source_directories_in_fixtures_path)
+    end
+
+    def source_directories_in_fixtures_path
+      Dir[File.join(FIXTURES_PATH, "**", "src")]
+    end
 end

test/preprocessor_test.rb → test/test_preprocessor.rb

@@ -2,7 +2,7 @@
 
 class PreprocessorTest < Test::Unit::TestCase
   def setup
-    @environment  = Sprockets::Environment.new(FIXTURES_PATH, source_directories_in_fixtures_path)
+    @environment  = environment_for_fixtures
     @preprocessor = Sprockets::Preprocessor.new(@environment)
   end
 
@@ -89,8 +89,4 @@ def assert_output_file_contains(indented_text)
       unindented_text = lines.map { |line| line[initial_indent..-1] }.join($/)
       assert output_text[unindented_text]
     end
-
-    def source_directories_in_fixtures_path
-      Dir[File.join(FIXTURES_PATH, "**", "src")]
-    end
 end