feat(Guard): add Guard to the project (ruby-formatter#12)

* feat(Guard): Add Guard to the project

* feat(Guard): Organize spec files

Organize files in the `spec` directory to follow the convenionts of a vanilla Guard setup.

* feat(Guard): move `rufo_spec`s into `formatter_spec`

Since all of the tests in `spec/rufo_spec` are really testing the formatter, let's move those tests into `spec/lib/rufo/formatter_spec` where they belong.

* fix(rufo_spec): rm `rufo_spec`

Now that the tests are moved into `formatter_spec`, we can rm `rufo_spec`.

Guardfile

@@ -0,0 +1,5 @@
+guard :rspec, cmd: 'rspec' do
+  watch(%r{^spec/.+_spec\.rb$})
+  watch(%r{^lib/(.+)\.rb$}) { |m| "spec/lib/#{m[1]}_spec.rb" }
+  watch('spec/spec_helper.rb') { "spec" }
+end

rufo.gemspec

@@ -24,4 +24,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", "~> 1.15"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"
+  spec.add_development_dependency "guard-rspec", "~> 4.0"
 end

spec/rufo_spec.rb → spec/lib/rufo/formatter_spec.rb

@@ -67,13 +67,13 @@ def assert_format(code, expected = code, **options)
   ex.metadata[:line_number] = line
 end
 
-RSpec.describe Rufo do
-  Dir[File.join(FILE_PATH, "/source_specs/*")].each do |source_specs|
+RSpec.describe Rufo::Formatter do
+  Dir[File.join(FILE_PATH, "/formatter_source_specs/*")].each do |source_specs|
     assert_source_specs(source_specs) if File.file?(source_specs)
   end
 
   if VERSION >= Gem::Version.new("2.3")
-    Dir[File.join(FILE_PATH, "/source_specs/2.3/*")].each do |source_specs|
+    Dir[File.join(FILE_PATH, "/formatter_source_specs/2.3/*")].each do |source_specs|
       assert_source_specs(source_specs) if File.file?(source_specs)
     end
   end