 
     * `:test_pattern` - a pattern to load test files, defaults to `*_test.exs`.
 
-    * `:warn_test_pattern` - a pattern to match potentially missed test files 
+    * `:warn_test_pattern` - a pattern to match potentially missed test files
       and display a warning, defaults to `*_test.ex`.
 
     * `:test_coverage` - a set of options to be passed down to the coverage

    end

    project = Mix.Project.config
    cover   = Keyword.merge(@cover, project[:test_coverage] || [])

    # Start cover after we load deps but before we start the app.
    cover =
      if opts[:cover] do
        cover[:tool].start(Mix.Project.compile_path(project), cover)
      end


    warn_test_pattern = project[:warn_test_pattern] || "*_test.ex"

    matched_test_files = Mix.Utils.extract_files(test_files, test_pattern)
    matched_warn_test_files =
      Mix.Utils.extract_files(test_files, warn_test_pattern) -- matched_test_files

    display_warn_test_pattern(matched_warn_test_files, test_pattern)

    case matched_test_files do
      [] ->
        Mix.shell.error "Test patterns did not match any file: " <> Enum.join(files, ", ")
