Add support for enforced symbolized shared examples

* Existing check only allows to enforce one style, which is called "titelized" in the error message but really just looks for a string type. * Enforcing the existing style raises an error when a shared example uses a symbol definition rather than a string. * But there are some benefits to using symbol types instead, as is discussed here: https://gitlab.com/gitlab-org/gitlab/-/issues/427697 * As a result, some codebases might want to enforce a symbol type instead.
rubocop · Nov 22, 2023 · 60ce214 · 60ce214
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Master (Unreleased)
 
+- Add support for `symbol` style for `RSpec/SharedExamples`. ([@jessieay])
+
 ## 2.25.0 (2023-10-27)
 
 - Add support single quoted string and percent string and heredoc for `RSpec/Rails/HttpStatus`. ([@ydah])
@@ -856,6 +858,7 @@ Compatibility release so users can upgrade RuboCop to 0.51.0. No new features.
 [@jaredbeck]: https://github.com/jaredbeck
 [@jaredmoody]: https://github.com/jaredmoody
 [@jeffreyc]: https://github.com/jeffreyc
+[@jessieay]: https://github.com/jessieay
 [@jfragoulis]: https://github.com/jfragoulis
 [@johnny-miyake]: https://github.com/johnny-miyake
 [@jojos003]: https://github.com/jojos003

diff --git a/config/default.yml b/config/default.yml
@@ -832,9 +832,14 @@ RSpec/SharedContext:
   Reference: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/SharedContext
 
 RSpec/SharedExamples:
-  Description: Enforces use of string to titleize shared examples.
+  Description: Checks for consistent style for shared example names.
   Enabled: true
+  EnforcedStyle: string
+  SupportedStyles:
+    - string
+    - symbol
   VersionAdded: '1.25'
+  VersionChanged: "<<next>>"
   Reference: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/SharedExamples
 
 RSpec/SingleArgumentMessageChain:

diff --git a/lib/rubocop/cop/rspec/shared_examples.rb b/lib/rubocop/cop/rspec/shared_examples.rb
@@ -3,9 +3,14 @@
 module RuboCop
   module Cop
     module RSpec
-      # Enforces use of string to titleize shared examples.
+      # Checks for consistent style for shared example names.
       #
-      # @example
+      # Enforces either `string` or `symbol` for shared example
+      # names.
+      #
+      # This cop can be configured using the `EnforcedStyle` option
+      #
+      # @example `EnforcedStyle: string` (default)
       #   # bad
       #   it_behaves_like :foo_bar_baz
       #   it_should_behave_like :foo_bar_baz
@@ -20,8 +25,24 @@ module RSpec
       #   shared_examples_for 'foo bar baz'
       #   include_examples 'foo bar baz'
       #
+      # @example `EnforcedStyle: symbol`
+      #   # bad
+      #   it_behaves_like 'foo bar baz'
+      #   it_should_behave_like 'foo bar baz'
+      #   shared_examples 'foo bar baz'
+      #   shared_examples_for 'foo bar baz'
+      #   include_examples 'foo bar baz'
+      #
+      #   # good
+      #   it_behaves_like :foo_bar_baz
+      #   it_should_behave_like :foo_bar_baz
+      #   shared_examples :foo_bar_baz
+      #   shared_examples_for :foo_bar_baz
+      #   include_examples :foo_bar_baz
+      #
       class SharedExamples < Base
         extend AutoCorrector
+        include ConfigurableEnforcedStyle
 
         # @!method shared_examples(node)
         def_node_matcher :shared_examples, <<~PATTERN
@@ -34,19 +55,38 @@ class SharedExamples < Base
         def on_send(node)
           shared_examples(node) do
             ast_node = node.first_argument
-            next unless ast_node&.sym_type?
+            next unless offense?(node.first_argument)
 
-            checker = Checker.new(ast_node)
+            checker = new_checker(ast_node)
             add_offense(checker.node, message: checker.message) do |corrector|
               corrector.replace(checker.node, checker.preferred_style)
             end
           end
         end
 
+        private
+
+        def offense?(ast_node)
+          if style == :symbol
+            ast_node&.str_type?
+          else # string
+            ast_node&.sym_type?
+          end
+        end
+
+        def new_checker(ast_node)
+          if style == :symbol
+            SymbolChecker.new(ast_node)
+          else # string
+            StringChecker.new(ast_node)
+          end
+
+        end
+
         # :nodoc:
-        class Checker
+        class SymbolChecker
           MSG = 'Prefer %<prefer>s over `%<current>s` ' \
-                'to titleize shared examples.'
+                'to symbolize shared examples.'
 
           attr_reader :node
 
@@ -55,22 +95,30 @@ def initialize(node)
           end
 
           def message
-            format(MSG, prefer: preferred_style, current: symbol.inspect)
+            format(MSG, prefer: preferred_style, current: node.value.inspect)
           end
 
           def preferred_style
-            string = symbol.to_s.tr('_', ' ')
-            wrap_with_single_quotes(string)
+            ":#{node.value.to_s.downcase.tr(' ', '_')}"
           end
+        end
+
+        class StringChecker
+          MSG = 'Prefer %<prefer>s over `%<current>s` ' \
+                'to titleize shared examples.'
 
-          private
+          attr_reader :node
 
-          def symbol
-            node.value
+          def initialize(node)
+            @node = node
           end
 
-          def wrap_with_single_quotes(string)
-            "'#{string}'"
+          def message
+            format(MSG, prefer: preferred_style, current: node.value.inspect)
+          end
+
+          def preferred_style
+            "'#{node.value.to_s.tr('_', ' ')}'"
           end
         end
       end

diff --git a/spec/rubocop/cop/rspec/shared_examples_spec.rb b/spec/rubocop/cop/rspec/shared_examples_spec.rb
@@ -1,8 +1,9 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::RSpec::SharedExamples do
-  it 'registers an offense when using symbolic title' do
-    expect_offense(<<-RUBY)
+  context 'when using default (string) enforced style' do
+    it 'registers an offense when using symbolic title' do
+      expect_offense(<<-RUBY)
       it_behaves_like :foo_bar_baz
                       ^^^^^^^^^^^^ Prefer 'foo bar baz' over `:foo_bar_baz` to titleize shared examples.
       it_should_behave_like :foo_bar_baz
@@ -16,33 +17,33 @@
       include_examples :foo_bar_baz, 'foo', 'bar'
                        ^^^^^^^^^^^^ Prefer 'foo bar baz' over `:foo_bar_baz` to titleize shared examples.
 
-      shared_examples :foo_bar_baz, 'foo', 'bar' do |param|
+      shared_examples :foo_bar_baz, 'foo', 'bar', :foo_bar, 5 do |param|
                       ^^^^^^^^^^^^ Prefer 'foo bar baz' over `:foo_bar_baz` to titleize shared examples.
         # ...
       end
 
       RSpec.shared_examples :foo_bar_baz
                             ^^^^^^^^^^^^ Prefer 'foo bar baz' over `:foo_bar_baz` to titleize shared examples.
-    RUBY
+      RUBY
 
-    expect_correction(<<-RUBY)
+      expect_correction(<<-RUBY)
       it_behaves_like 'foo bar baz'
       it_should_behave_like 'foo bar baz'
       shared_examples 'foo bar baz'
       shared_examples_for 'foo bar baz'
       include_examples 'foo bar baz'
       include_examples 'foo bar baz', 'foo', 'bar'
 
-      shared_examples 'foo bar baz', 'foo', 'bar' do |param|
+      shared_examples 'foo bar baz', 'foo', 'bar', :foo_bar, 5 do |param|
         # ...
       end
 
       RSpec.shared_examples 'foo bar baz'
-    RUBY
-  end
+      RUBY
+    end
 
-  it 'does not register an offense when using string title' do
-    expect_no_offenses(<<-RUBY)
+    it 'does not register an offense when using string title' do
+      expect_no_offenses(<<-RUBY)
       it_behaves_like 'foo bar baz'
       it_should_behave_like 'foo bar baz'
       shared_examples 'foo bar baz'
@@ -53,11 +54,11 @@
       shared_examples 'foo bar baz', 'foo', 'bar' do |param|
         # ...
       end
-    RUBY
-  end
+      RUBY
+    end
 
-  it 'does not register an offense when using Module/Class title' do
-    expect_no_offenses(<<-RUBY)
+    it 'does not register an offense when using Module/Class title' do
+      expect_no_offenses(<<-RUBY)
       it_behaves_like FooBarBaz
       it_should_behave_like FooBarBaz
       shared_examples FooBarBaz
@@ -68,6 +69,86 @@
       shared_examples FooBarBaz, 'foo', 'bar' do |param|
         # ...
       end
-    RUBY
+      RUBY
+    end
+  end
+
+  context 'when using symbol enforced style' do
+    let(:cop_config) { { 'EnforcedStyle' => 'symbol' } }
+
+    it 'registers an offense when using string title' do
+      expect_offense(<<-RUBY)
+      it_behaves_like 'foo bar baz'
+                      ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+      it_should_behave_like 'foo bar baz'
+                            ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+      shared_examples 'foo bar baz'
+                      ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+      shared_examples_for 'foo bar baz'
+                          ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+      include_examples 'foo bar baz'
+                       ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+      include_examples 'Foo Bar Baz'
+                       ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"Foo Bar Baz"` to symbolize shared examples.
+      include_examples 'foo bar baz', 'foo', 'bar'
+                       ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+
+      shared_examples 'foo bar baz', 'foo', 'bar' do |param|
+                      ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+        # ...
+      end
+
+      RSpec.shared_examples 'foo bar baz'
+                            ^^^^^^^^^^^^^ Prefer :foo_bar_baz over `"foo bar baz"` to symbolize shared examples.
+      RUBY
+
+      expect_correction(<<-RUBY)
+      it_behaves_like :foo_bar_baz
+      it_should_behave_like :foo_bar_baz
+      shared_examples :foo_bar_baz
+      shared_examples_for :foo_bar_baz
+      include_examples :foo_bar_baz
+      include_examples :foo_bar_baz
+      include_examples :foo_bar_baz, 'foo', 'bar'
+
+      shared_examples :foo_bar_baz, 'foo', 'bar' do |param|
+        # ...
+      end
+
+      RSpec.shared_examples :foo_bar_baz
+      RUBY
+    end
+
+    it 'does not register an offense when using symbol' do
+      expect_no_offenses(<<-RUBY)
+      it_behaves_like :foo_bar_baz
+      it_should_behave_like :foo_bar_baz
+      shared_examples :foo_bar_baz
+      shared_examples_for :foo_bar_baz
+      include_examples :foo_bar_baz
+      include_examples :foo_bar_baz, :foo, :bar
+
+      shared_examples :foo_bar_baz, 'foo', 'bar', 'foo bar', 5 do |param|
+        # ...
+      end
+
+      RSpec.shared_examples :foo_bar_baz
+      RUBY
+    end
+
+    it 'does not register an offense when using Module/Class title' do
+      expect_no_offenses(<<-RUBY)
+      it_behaves_like FooBarBaz
+      it_should_behave_like FooBarBaz
+      shared_examples FooBarBaz
+      shared_examples_for FooBarBaz
+      include_examples FooBarBaz
+      include_examples FooBarBaz, 'foo', 'bar'
+
+      shared_examples FooBarBaz, 'foo', 'bar', 'foo bar', 5 do |param|
+        # ...
+      end
+      RUBY
+    end
   end
 end