Merge pull request #994 from biinari/feature/repeated_include_examples

Add cop RSpec/RepeatedIncludeExample

Author: pirj

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Master (Unreleased)
 
+* Add `RSpec/RepeatedIncludeExample` cop. ([@biinari][])
+
 ## 1.43.1 (2020-08-17)
 
 * Fix `RSpec/FilePath` when checking a file defining e.g. an empty class. ([@bquorning][])
@@ -550,3 +552,4 @@ Compatibility release so users can upgrade RuboCop to 0.51.0. No new features.
 [@mlarraz]: https://github.com/mlarraz
 [@jtannas]: https://github.com/jtannas
 [@mockdeep]: https://github.com/mockdeep
+[@biinari]: https://github.com/biinari

config/default.yml

@@ -494,6 +494,12 @@ RSpec/RepeatedExampleGroupDescription:
   VersionAdded: '1.38'
   StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/RepeatedExampleGroupDescription
 
+RSpec/RepeatedIncludeExample:
+  Description: Check for repeated include of shared examples.
+  Enabled: true
+  VersionAdded: '1.44'
+  StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/RepeatedIncludeExample
+
 RSpec/ReturnFromStub:
   Description: Checks for consistent style of stub's return setting.
   Enabled: true

lib/rubocop/cop/rspec/repeated_include_example.rb

@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module RSpec
+      # Check for repeated include of shared examples.
+      #
+      # @example
+      #
+      #    # bad
+      #    describe 'foo' do
+      #      include_examples 'cool stuff'
+      #      include_examples 'cool stuff'
+      #    end
+      #
+      #    # bad
+      #    describe 'foo' do
+      #      it_behaves_like 'a cool', 'thing'
+      #      it_behaves_like 'a cool', 'thing'
+      #    end
+      #
+      #    # bad
+      #    context 'foo' do
+      #      it_should_behave_like 'a duck'
+      #      it_should_behave_like 'a duck'
+      #    end
+      #
+      #    # good
+      #    describe 'foo' do
+      #      include_examples 'cool stuff'
+      #    end
+      #
+      #    describe 'bar' do
+      #      include_examples 'cool stuff'
+      #    end
+      #
+      #    # good
+      #    describe 'foo' do
+      #      it_behaves_like 'a cool', 'thing'
+      #      it_behaves_like 'a cool', 'person'
+      #    end
+      #
+      #    # good
+      #    context 'foo' do
+      #      it_should_behave_like 'a duck'
+      #      it_should_behave_like 'a goose'
+      #    end
+      #
+      class RepeatedIncludeExample < Base
+        MSG = 'Repeated include of shared_examples %<name>s ' \
+          'on line(s) %<repeat>s'
+
+        def_node_matcher :several_include_examples?, <<-PATTERN
+          (begin <#include_examples? #include_examples? ...>)
+        PATTERN
+
+        def_node_matcher :include_examples?, Includes::EXAMPLES.send_pattern
+
+        def_node_matcher :shared_examples_name, <<-PATTERN
+          (send _ #{Includes::EXAMPLES.node_pattern_union} $_ ...)
+        PATTERN
+
+        def on_begin(node)
+          return unless several_include_examples?(node)
+
+          repeated_include_examples(node).each do |item, repeats|
+            add_offense(item, message: message(item, repeats))
+          end
+        end
+
+        private
+
+        def repeated_include_examples(node)
+          node
+            .children
+            .select { |child| literal_include_examples?(child) }
+            .group_by { |child| signature_keys(child) }
+            .values
+            .reject(&:one?)
+            .flat_map { |items| add_repeated_lines(items) }
+        end
+
+        def literal_include_examples?(node)
+          include_examples?(node) &&
+            node.arguments.all?(&:recursive_literal_or_const?)
+        end
+
+        def add_repeated_lines(items)
+          repeated_lines = items.map(&:first_line)
+          items.map { |item| [item, repeated_lines - [item.first_line]] }
+        end
+
+        def signature_keys(item)
+          item.arguments
+        end
+
+        def message(item, repeats)
+          format(MSG, name: shared_examples_name(item).source, repeat: repeats)
+        end
+      end
+    end
+  end
+end

lib/rubocop/cop/rspec_cops.rb

@@ -79,6 +79,7 @@
 require_relative 'rspec/repeated_example'
 require_relative 'rspec/repeated_example_group_body'
 require_relative 'rspec/repeated_example_group_description'
+require_relative 'rspec/repeated_include_example'
 require_relative 'rspec/return_from_stub'
 require_relative 'rspec/scattered_let'
 require_relative 'rspec/scattered_setup'

manual/cops.md

@@ -78,6 +78,7 @@
 * [RSpec/RepeatedExample](cops_rspec.md#rspecrepeatedexample)
 * [RSpec/RepeatedExampleGroupBody](cops_rspec.md#rspecrepeatedexamplegroupbody)
 * [RSpec/RepeatedExampleGroupDescription](cops_rspec.md#rspecrepeatedexamplegroupdescription)
+* [RSpec/RepeatedIncludeExample](cops_rspec.md#rspecrepeatedincludeexample)
 * [RSpec/ReturnFromStub](cops_rspec.md#rspecreturnfromstub)
 * [RSpec/ScatteredLet](cops_rspec.md#rspecscatteredlet)
 * [RSpec/ScatteredSetup](cops_rspec.md#rspecscatteredsetup)

manual/cops_rspec.md

@@ -2828,6 +2828,61 @@ end
 
 * [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/RepeatedExampleGroupDescription](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/RepeatedExampleGroupDescription)
 
+## RSpec/RepeatedIncludeExample
+
+Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+--- | --- | --- | --- | ---
+Enabled | Yes | No | 1.44 | -
+
+Check for repeated include of shared examples.
+
+### Examples
+
+```ruby
+# bad
+describe 'foo' do
+  include_examples 'cool stuff'
+  include_examples 'cool stuff'
+end
+
+# bad
+describe 'foo' do
+  it_behaves_like 'a cool', 'thing'
+  it_behaves_like 'a cool', 'thing'
+end
+
+# bad
+context 'foo' do
+  it_should_behave_like 'a duck'
+  it_should_behave_like 'a duck'
+end
+
+# good
+describe 'foo' do
+  include_examples 'cool stuff'
+end
+
+describe 'bar' do
+  include_examples 'cool stuff'
+end
+
+# good
+describe 'foo' do
+  it_behaves_like 'a cool', 'thing'
+  it_behaves_like 'a cool', 'person'
+end
+
+# good
+context 'foo' do
+  it_should_behave_like 'a duck'
+  it_should_behave_like 'a goose'
+end
+```
+
+### References
+
+* [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/RepeatedIncludeExample](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/RepeatedIncludeExample)
+
 ## RSpec/ReturnFromStub
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged