WIP: Rspec aliases

lib/rubocop-rspec.rb

@@ -13,6 +13,7 @@
 require_relative 'rubocop/rspec/wording'
 require_relative 'rubocop/rspec/language'
 require_relative 'rubocop/rspec/language/node_pattern'
+require_relative 'rubocop/rspec/config_shortcuts'
 require_relative 'rubocop/rspec/concept'
 require_relative 'rubocop/rspec/example_group'
 require_relative 'rubocop/rspec/example'

lib/rubocop/cop/rspec/cop.rb

@@ -40,6 +40,7 @@ module RSpec
       class Cop < WorkaroundCop
         include RuboCop::RSpec::Language
         include RuboCop::RSpec::Language::NodePattern
+        include RuboCop::RSpec::ConfigShortcuts
 
         DEFAULT_CONFIGURATION =
           RuboCop::RSpec::CONFIG.fetch('AllCops').fetch('RSpec')

lib/rubocop/cop/rspec/empty_hook.rb

@@ -27,12 +27,14 @@ class EmptyHook < Cop
 
         MSG = 'Empty hook detected.'
 
-        def_node_matcher :empty_hook?, <<~PATTERN
-          (block $#{Hooks::ALL.send_pattern} _ nil?)
+        def_node_matcher :empty_block?, <<~PATTERN
+          (block $#{Patterns::SEND_PATTERN} _ nil?)
         PATTERN
 
         def on_block(node)
-          empty_hook?(node) do |hook|
+          return unless hook?(node)
+
+          empty_block?(node) do |hook|
             add_offense(hook)
           end
         end

lib/rubocop/cop/rspec/scattered_setup.rb

@@ -42,7 +42,7 @@ def on_block(node)
         end
 
         def repeated_hooks(node)
-          hooks = RuboCop::RSpec::ExampleGroup.new(node)
+          hooks = RuboCop::RSpec::ExampleGroup.new(node, config)
             .hooks
             .select(&:knowable_scope?)
             .group_by { |hook| [hook.name, hook.scope, hook.metadata] }

lib/rubocop/rspec/concept.rb

@@ -6,10 +6,12 @@ module RSpec
     class Concept
       include Language
       include Language::NodePattern
+      include ConfigShortcuts
       extend NodePattern::Macros
 
-      def initialize(node)
+      def initialize(node, config = nil)
         @node = node
+        @config = config
       end
 
       def eql?(other)
@@ -29,6 +31,7 @@ def to_node
       protected
 
       attr_reader :node
+      attr_reader :config
     end
   end
 end

lib/rubocop/rspec/config_shortcuts.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module RSpec
+    # Config shortcuts for RuboCop::Cop::Rspec::Cop
+    # and Rubocop::RSpec::ExampleGroup
+    module ConfigShortcuts
+      def rspec_aliases(setting)
+        config
+          .for_all_cops
+          .fetch('RSpec', {})
+          .fetch('Aliases', {})
+          .fetch(setting, [])
+          .map(&:to_sym)
+      end
+    end
+  end
+end

lib/rubocop/rspec/language.rb

@@ -6,6 +6,16 @@ module RSpec
     module Language
       RSPEC = '{(const {nil? cbase} :RSpec) nil?}'
 
+      module Patterns
+        BLOCK_PATTERN = <<-PATTERN
+          (block (send {(const {nil? cbase} :RSpec) nil?} $_ ...) ...)
+        PATTERN
+
+        SEND_PATTERN = <<-PATTERN
+          (send {(const {nil? cbase} :RSpec) nil?} $_ ...)
+        PATTERN
+      end
+
       # Set of method selectors
       class SelectorSet
         def initialize(selectors)
@@ -91,17 +101,17 @@ module Examples
       end
 
       module Hooks
-        ALL = SelectorSet.new(
-          %i[
-            prepend_before
-            before
-            append_before
-            around
-            prepend_after
-            after
-            append_after
-          ]
-        )
+        NAMES = %i[
+          prepend_before
+          before
+          append_before
+          around
+          prepend_after
+          after
+          append_after
+        ].freeze
+
+        ALL = SelectorSet.new(NAMES)
 
         module Scopes
           ALL = SelectorSet.new(

lib/rubocop/rspec/language/node_pattern.rb

@@ -15,11 +15,18 @@ module NodePattern
 
         def_node_matcher :example?, Examples::ALL.block_pattern
 
-        def_node_matcher :hook?, Hooks::ALL.block_pattern
+        def hook?(node)
+          block_pattern(node) do |hook|
+            hooks = Hooks::NAMES + rspec_aliases('Hooks')
+            hooks.include?(hook)
+          end
+        end
 
         def_node_matcher :let?, Helpers::ALL.block_or_block_pass_pattern
 
         def_node_matcher :subject?, Subject::ALL.block_pattern
+
+        def_node_matcher :block_pattern, Patterns::BLOCK_PATTERN
       end
     end
   end

spec/rubocop/cop/rspec/empty_hook_spec.rb

@@ -240,4 +240,30 @@
       RUBY
     end
   end
+
+  # TODO: These tests just demonstrate that hooks aliases work in rewritten cops
+  context 'with `custom_hook` hook' do
+    it 'does NOT detect offense for empty NOT configured hook' do
+      expect_no_offenses(<<~RUBY)
+        custom_hook {}
+      RUBY
+    end
+
+    context 'when `custom_hook` is configured in AllCops.RSpec.Aliases.Hooks' do
+      include_context 'config'
+
+      let(:all_cops_config) do
+        { 'RSpec' => { 'Aliases' => { 'Hooks' => %w[custom_hook] } } }
+      end
+
+      it 'detects offense for empty configured hook' do
+        expect_offense(<<~RUBY)
+          custom_hook {}
+          ^^^^^^^^^^^ Empty hook detected.
+        RUBY
+
+        expect_correction('')
+      end
+    end
+  end
 end

spec/rubocop/cop/rspec/expect_in_hook_spec.rb

@@ -76,4 +76,30 @@
       end
     RUBY
   end
+
+  # TODO: These tests just demonstrate that hooks aliases work in rewritten cops
+  it 'does NOT add an offense for `expect` with block in `custom_hook` hook' do
+    expect_no_offenses(<<-RUBY)
+      setup do
+        expect { something }.to eq('foo')
+      end
+    RUBY
+  end
+
+  context 'when `custom_hook` is configured in AllCops.RSpec.Aliases.Hooks' do
+    include_context 'config'
+
+    let(:all_cops_config) do
+      { 'RSpec' => { 'Aliases' => { 'Hooks' => %w[custom_hook] } } }
+    end
+
+    it 'adds an offense for `expect` with block in `custom_hook` hook' do
+      expect_offense(<<-RUBY)
+        custom_hook do
+          expect { something }.to eq('foo')
+          ^^^^^^ Do not use `expect` in `custom_hook` hook
+        end
+      RUBY
+    end
+  end
 end