Convert brew tap-new test to spec.

Library/Homebrew/test/cmd/tap-new_spec.rb

@@ -0,0 +1,10 @@
+describe "brew tap-new", :integration_test do
+  it "initializes a new Tap with a ReadMe file" do
+    expect { brew "tap-new", "homebrew/foo", "--verbose" }
+      .to be_a_success
+      .and not_to_output.to_stdout
+      .and not_to_output.to_stderr
+
+    expect(HOMEBREW_LIBRARY/"Taps/homebrew/homebrew-foo/README.md").to exist
+  end
+end

Library/Homebrew/test/tap_new_test.rb

@@ -1,9 +0,0 @@
-require "testing_env"
-
-class IntegrationCommandTestTapNew < IntegrationCommandTestCase
-  def test_tap_readme
-    assert_equal "", cmd("tap-new", "homebrew/foo", "--verbose")
-    readme = HOMEBREW_LIBRARY/"Taps/homebrew/homebrew-foo/README.md"
-    assert readme.exist?, "The README should be created"
-  end
-end