Add RSpec support for integration commands.

Library/Homebrew/test/spec_helper.rb

@@ -16,6 +16,7 @@ require "tap"
 
 require "test/support/helper/shutup"
 require "test/support/helper/fixtures"
+require "test/support/helper/spec/shared_context/integration_test"
 
 TEST_DIRECTORIES = [
   CoreTap.instance.path/"Formula",

Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb

@@ -0,0 +1,94 @@
+require "rspec"
+require "open3"
+
+RSpec::Matchers.define_negated_matcher :not_to_output, :output
+RSpec::Matchers.define_negated_matcher :be_a_failure, :be_a_success
+
+RSpec.shared_context "integration test" do
+  extend RSpec::Matchers::DSL
+
+  matcher :be_a_success do
+    match do |actual|
+      status = actual.is_a?(Proc) ? actual.call : actual
+      status.respond_to?(:success?) && status.success?
+    end
+
+    def supports_block_expectations?
+      true
+    end
+
+    # It needs to be nested like this:
+    #
+    #   expect {
+    #     expect {
+    #       # command
+    #     }.to be_a_success
+    #   }.to output(something).to_stdout
+    #
+    # rather than this:
+    #
+    #   expect {
+    #     expect {
+    #       # command
+    #     }.to output(something).to_stdout
+    #   }.to be_a_success
+    #
+    def expects_call_stack_jump?
+      true
+    end
+  end
+
+  before(:each) do
+    (HOMEBREW_PREFIX/"bin").mkpath
+    FileUtils.touch HOMEBREW_PREFIX/"bin/brew"
+  end
+
+  after(:each) do
+    FileUtils.rm HOMEBREW_PREFIX/"bin/brew"
+    FileUtils.rmdir HOMEBREW_PREFIX/"bin"
+  end
+
+  # Generate unique ID to be able to
+  # properly merge coverage results.
+  def command_id_from_args(args)
+    @command_count ||= 0
+    pretty_args = args.join(" ").gsub(TEST_TMPDIR, "@TMPDIR@")
+    file_and_line = caller[1].sub(/(.*\d+):.*/, '\1')
+                             .sub("#{HOMEBREW_LIBRARY_PATH}/test/", "")
+    "#{file_and_line}:brew #{pretty_args}:#{@command_count += 1}"
+  end
+
+  # Runs a `brew` command with the test configuration
+  # and with coverage reporting enabled.
+  def brew(*args)
+    env = args.last.is_a?(Hash) ? args.pop : {}
+
+    env.merge!(
+      "HOMEBREW_BREW_FILE" => HOMEBREW_PREFIX/"bin/brew",
+      "HOMEBREW_INTEGRATION_TEST" => command_id_from_args(args),
+      "HOMEBREW_TEST_TMPDIR" => TEST_TMPDIR,
+      "HOMEBREW_DEVELOPER" => ENV["HOMEBREW_DEVELOPER"],
+    )
+
+    ruby_args = [
+      "-W0",
+      "-I", "#{HOMEBREW_LIBRARY_PATH}/test/support/lib",
+      "-I", HOMEBREW_LIBRARY_PATH.to_s,
+      "-rconfig"
+    ]
+    ruby_args << "-rsimplecov" if ENV["HOMEBREW_TESTS_COVERAGE"]
+    ruby_args << "-rtest/support/helper/integration_mocks"
+    ruby_args << (HOMEBREW_LIBRARY_PATH/"brew.rb").resolved_path.to_s
+
+    Bundler.with_original_env do
+      stdout, stderr, status = Open3.capture3(env, RUBY_PATH, *ruby_args, *args)
+      $stdout.print stdout
+      $stderr.print stderr
+      status
+    end
+  end
+end
+
+RSpec.configure do |config|
+  config.include_context "integration test", :integration_test
+end