Merge pull request #2124 from reitermarkus/spec-upgrade

Convert `brew upgrade` test to spec.

Library/Homebrew/test/cmd/upgrade_spec.rb

+describe "brew upgrade", :integration_test do
+  it "upgrades a Formula to the latest version" do
+    setup_test_formula "testball"
+    (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath
+
+    shutup do
+      expect { brew "upgrade" }.to be_a_success
+    end
+
+    expect(HOMEBREW_CELLAR/"testball/0.1").to be_a_directory
+  end
+end

Library/Homebrew/test/upgrade_test.rb

-require "testing_env"
-
-class IntegrationCommandTestUpgrade < IntegrationCommandTestCase
-  def test_upgrade
-    setup_test_formula "testball"
-    (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath
-
-    cmd("upgrade")
-    assert((HOMEBREW_CELLAR/"testball/0.1").directory?,
-      "The latest version directory should be created")
-  end
-end