Add tests for Rake task creation

test/tests/test_rake_task.rb

+require 'fileutils'
+require 'tmpdir'
+
+class RakeTaskTests < Test::Unit::TestCase
+  def setup
+    # Brakeman is noisy on errors
+    @old_stderr = $stderr.dup
+    $stderr.reopen("/dev/null", "w")
+  end
+
+  def cleanup
+    $stderr = old_stderr
+  end
+
+  def in_temp_app
+    Dir.mktmpdir do |dir|
+      FileUtils.cp_r "#{TEST_PATH}/apps/rails3.2/.", dir
+
+      @rake_task = "#{dir}/lib/tasks/brakeman.rake"
+      @rakefile = "#{dir}/Rakefile"
+
+      current_dir = FileUtils.pwd
+      FileUtils.cd dir
+
+      yield dir
+
+      FileUtils.cd current_dir
+    end
+  end
+
+  def test_create_rake_task
+    in_temp_app do
+      assert_nothing_raised SystemExit do
+        Brakeman.install_rake_task
+      end
+
+      assert File.exist? @rake_task
+    end
+  end
+
+  def test_rake_task_exists
+    in_temp_app do
+      assert_nothing_raised SystemExit do
+        Brakeman.install_rake_task
+      end
+
+      assert_raise SystemExit do
+        Brakeman.install_rake_task
+      end
+    end
+  end
+
+  def test_rake_no_Rakefile
+    in_temp_app do
+      File.delete @rakefile
+
+      assert_raise SystemExit do
+        Brakeman.install_rake_task
+      end
+    end
+  end
+end