Revert "Fix status code in mix test"

This reverts commit 4fc3fc1.

We want to run all mix umbrella projects together, because
all their apps are booted together and we should not pretend
otherwise.

Author: José Valim

lib/ex_unit/lib/ex_unit.ex

@@ -108,7 +108,7 @@ defmodule ExUnit do
         0 ->
           failures = ExUnit.run
           System.at_exit fn _ ->
-            if failures > 0, do: System.halt(1), else: System.halt(0)
+            if failures > 0, do: System.halt(1)
           end
         _ ->
           :ok

lib/mix/lib/mix/tasks/test.ex

@@ -2,28 +2,24 @@ defmodule Mix.Tasks.Test do
   defmodule Cover do
     @moduledoc false
 
-    def run(compile_path, opts, callback) do
-      Mix.shell.info "Cover compiling modules ...\n"
+    def start(compile_path, opts) do
+      Mix.shell.info "Cover compiling modules ... "
       :cover.start
       :cover.compile_beam_directory(compile_path |> to_char_list)
 
-      output = opts[:output]
-      callback.()
+      if :application.get_env(:cover, :started) != { :ok, true } do
+        output = opts[:output]
 
-      Mix.shell.info "\nGenerating cover results ..."
-      File.mkdir_p!(output)
-      Enum.each :cover.modules, fn(mod) ->
-        :cover.analyse_to_file(mod, '#{output}/#{mod}.html', [:html])
-      end
-    end
-  end
+        System.at_exit fn(_) ->
+          Mix.shell.info "\nGenerating cover results ... "
+          File.mkdir_p!(output)
+          Enum.each :cover.modules, fn(mod) ->
+            :cover.analyse_to_file(mod, '#{output}/#{mod}.html', [:html])
+          end
+        end
 
-  defmodule Bare do
-    @moduledoc false
-
-    def run(_, _, fun) do
-      Mix.shell.info ""
-      fun.()
+        :application.set_env(:cover, :started, true)
+      end
     end
   end
 
@@ -75,8 +71,8 @@ defmodule Mix.Tasks.Test do
 
       test_coverage: [tool: CoverModule]
 
-  `CoverModule` can be any module that exports `run/3`, receiving the
-  compilation path, `test_coverage` options and the callback function as arguments.
+  `CoverModule` can be any module that exports `start/2`, receiving the
+  compilation path and the `test_coverage` options as arguments.
   """
 
   @switches [force: :boolean, color: :boolean, cover: :boolean,
@@ -96,11 +92,13 @@ defmodule Mix.Tasks.Test do
 
     project = Mix.project
     cover   = Keyword.merge(@cover, project[:test_coverage] || [])
-    wrapper = if opts[:cover], do: cover[:tool], else: Bare
+
+    if opts[:cover] do
+      cover[:tool].start(project[:compile_path], cover)
+    end
 
     :application.load(:ex_unit)
     opts = Dict.take(opts, [:trace, :max_cases, :color])
-    opts = Keyword.put(opts, :autorun, false)
     ExUnit.configure(opts)
 
     test_paths = project[:test_paths] || ["test"]
@@ -109,20 +107,8 @@ defmodule Mix.Tasks.Test do
     test_paths   = if files == [], do: test_paths, else: files
     test_pattern = project[:test_pattern] || "*_test.exs"
 
-    wrapper.run project[:compile_path], cover, fn -> do_run(test_paths, test_pattern) end
-  end
-
-  defp do_run(test_paths, test_pattern) do
     files = Mix.Utils.extract_files(test_paths, test_pattern)
-    Kernel.ParallelRequire.files(files)
-
-    failures = ExUnit.run
-    System.at_exit fn
-      0 ->
-        if failures > 0, do: System.halt(1), else: System.halt(0)
-      _ ->
-        :ok
-    end
+    Kernel.ParallelRequire.files files
   end
 
   defp require_test_helper(dir) do