Implement file and temp dir spec helpers

spec/spec_helper.rb

@@ -16,4 +16,7 @@ def load_support_files!
   config.mock_with(:rspec) { |mocks| mocks.verify_partial_doubles = true }
 
   config.order = :random
+
+  config.include FileHelper
+  config.include TempDirHelper
 end

spec/support/file_helper.rb

@@ -0,0 +1,31 @@
+module FileHelper
+  extend RSpec::Matchers::DSL
+
+  matcher :create_dir do |filename|
+    supports_block_expectations
+
+    match do |action|
+      path = File.join(@dir, filename)
+
+      expect(&action).to change { Dir.exist?(path) }.from(false).to(true)
+    end
+
+    chain :in do |dir|
+      @dir = dir
+    end
+  end
+
+  matcher :create_file do |filename|
+    supports_block_expectations
+
+    match do |action|
+      path = File.join(@dir, filename)
+
+      expect(&action).to change { File.exist?(path) }.from(false).to(true)
+    end
+
+    chain :in do |dir|
+      @dir = dir
+    end
+  end
+end

spec/support/temp_dir_helper.rb

@@ -0,0 +1,15 @@
+module TempDirHelper
+  RSpec.configure do |config|
+    config.around(with_temp_dir: true) do |spec|
+      self.class.class_eval { attr_reader :temp_dir }
+
+      Dir.mktmpdir do |temp_dir|
+        @temp_dir = temp_dir
+
+        spec.run
+
+        remove_instance_variable(:@temp_dir)
+      end
+    end
+  end
+end