install_test: add HEAD tests

Library/Homebrew/test/install_test.rb

@@ -72,6 +72,50 @@ class IntegrationCommandTestInstall < IntegrationCommandTestCase
       cmd("install", "testball1", "--force")
   end
 
+  def test_install_head_installed
+    initial_env = ENV.to_hash
+    %w[AUTHOR COMMITTER].each do |role|
+      ENV["GIT_#{role}_NAME"] = "brew tests"
+      ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
+      ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
+    end
+
+    repo_path = HOMEBREW_CACHE.join("repo")
+    repo_path.join("bin").mkpath
+
+    repo_path.cd do
+      shutup do
+        system "git", "init"
+        system "git", "remote", "add", "origin", "https://github.com/Homebrew/homebrew-foo"
+        FileUtils.touch "bin/something.bin"
+        FileUtils.touch "README"
+        system "git", "add", "--all"
+        system "git", "commit", "-m", "Initial repo commit"
+      end
+    end
+
+    setup_test_formula "testball1", <<-EOS.undent
+      version "1.0"
+      head "file://#{repo_path}", :using => :git
+      def install
+        prefix.install Dir["*"]
+      end
+    EOS
+
+    # Ignore dependencies, because we'll try to resolve requirements in build.rb
+    # and there will be the git requirement, but we cannot instantiate git
+    # formula since we only have testball1 formula.
+    assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-2ccdf4f", cmd("install", "testball1", "--HEAD", "--ignore-dependencies")
+    assert_match "testball1-HEAD-2ccdf4f already installed",
+      cmd("install", "testball1", "--HEAD", "--ignore-dependencies")
+    assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-2ccdf4f", cmd("unlink", "testball1")
+    assert_match "#{HOMEBREW_CELLAR}/testball1/1.0", cmd("install", "testball1")
+
+  ensure
+    ENV.replace(initial_env)
+    repo_path.rmtree
+  end
+
   def test_install_with_invalid_option
     setup_test_formula "testball1"
     assert_match "testball1: this formula has no --with-fo option so it will be ignored!",