diff --git a/lib/mix/test/mix/tasks/clean_test.exs b/lib/mix/test/mix/tasks/clean_test.exs
index 355a8b12ed0..87b90e9b3f9 100644
--- a/lib/mix/test/mix/tasks/clean_test.exs
+++ b/lib/mix/test/mix/tasks/clean_test.exs
@@ -1,4 +1,4 @@
-Code.require_file "../../test_helper.exs", __DIR__
+Code.require_file("../../test_helper.exs", __DIR__)
 
 defmodule Mix.Tasks.CleanTest do
   use MixTest.Case
@@ -17,18 +17,18 @@ defmodule Mix.Tasks.CleanTest do
   end
 
   setup do
-    Mix.Project.push Sample
+    Mix.Project.push(Sample)
     :ok
   end
 
   test "cleans the application build" do
     in_fixture "deps_status", fn ->
-      File.mkdir_p! "_build/dev/lib/sample/consolidated"
-      File.mkdir_p! "_build/dev/lib/sample"
-      File.mkdir_p! "_build/test/lib/sample"
-      File.mkdir_p! "_build/dev/lib/ok"
+      File.mkdir_p!("_build/dev/lib/sample/consolidated")
+      File.mkdir_p!("_build/dev/lib/sample")
+      File.mkdir_p!("_build/test/lib/sample")
+      File.mkdir_p!("_build/dev/lib/ok")
 
-      Mix.Tasks.Clean.run []
+      Mix.Tasks.Clean.run([])
       refute File.exists?("_build/dev/lib/sample/consolidated")
       refute File.exists?("_build/dev/lib/sample")
       refute File.exists?("_build/test/lib/sample")
@@ -38,14 +38,14 @@ defmodule Mix.Tasks.CleanTest do
 
   test "cleans dependencies build" do
     in_fixture "deps_status", fn ->
-      File.mkdir_p! "_build/dev/lib/ok"
-      File.mkdir_p! "_build/test/lib/ok"
+      File.mkdir_p!("_build/dev/lib/ok")
+      File.mkdir_p!("_build/test/lib/ok")
 
-      Mix.Tasks.Clean.run ["--deps", "--only", "dev"]
+      Mix.Tasks.Clean.run(["--deps", "--only", "dev"])
       refute File.exists?("_build/dev")
       assert File.exists?("_build/test")
 
-      Mix.Tasks.Clean.run ["--deps"]
+      Mix.Tasks.Clean.run(["--deps"])
       refute File.exists?("_build/test")
     end
   end