Add metadata detection to ScatteredSetup cop

pirj · pirj · commit 1c7a360a3b37 · 2020-01-03T23:43:23.000+03:00
RSpec allows hash metadata to be present when no explicit hook scope is given. However, if hook scope is omitted, symbolic metadata is not allowed, and that causes RSpec to raise an error. Fixes rubocop#850
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Master (Unreleased)
 
 * Fix `RSpec/InstanceVariable` detection inside custom matchers. ([@pirj][])
+* Fix `RSpec/ScatteredSetup` to distinguish hooks with different metadata. ([@pirj][])
 
 ## 1.37.1 (2019-12-16)
 
diff --git a/lib/rubocop/cop/rspec/scattered_setup.rb b/lib/rubocop/cop/rspec/scattered_setup.rb
@@ -36,8 +36,8 @@ def on_block(node)
         def analyzable_hooks(node)
           RuboCop::RSpec::ExampleGroup.new(node)
             .hooks
-            .select { |hook| hook.knowable_scope? && hook.valid_scope? }
-            .group_by { |hook| [hook.name, hook.scope] }
+            .select(&:knowable_scope?)
+            .group_by { |hook| [hook.name, hook.scope, hook.metadata] }
             .values
             .reject(&:one?)
             .flatten
diff --git a/lib/rubocop/rspec/hook.rb b/lib/rubocop/rspec/hook.rb
@@ -4,39 +4,72 @@ module RuboCop
   module RSpec
     # Wrapper for RSpec hook
     class Hook < Concept
-      STANDARDIZED_SCOPES = %i[each context suite].freeze
-      private_constant(:STANDARDIZED_SCOPES)
+      def_node_matcher :extract_metadata, <<~PATTERN
+        (block
+          {
+            (send _ _ #valid_scope? $...)
+            (send _ _ $...)
+          }
+          ...
+        )
+      PATTERN
 
       def name
         node.method_name
       end
 
       def knowable_scope?
-        return true unless scope_argument
-
-        scope_argument.sym_type?
-      end
-
-      def valid_scope?
-        STANDARDIZED_SCOPES.include?(scope)
+        scope_argument.nil? ||
+          scope_argument.sym_type? ||
+          scope_argument.hash_type?
       end
 
       def example?
         scope.equal?(:each)
       end
 
       def scope
+        return :each if scope_argument&.hash_type?
+
         case scope_name
         when nil, :each, :example then :each
         when :context, :all       then :context
         when :suite               then :suite
-        else
-          scope_name
         end
       end
 
+      def metadata
+        (extract_metadata(node) || [])
+          .map { |meta| transform_metadata(meta) }
+          .flatten
+          .inject(&:merge)
+      end
+
       private
 
+      def valid_scope?(node)
+        node&.sym_type? && Hooks::Scopes::ALL.include?(node.value)
+      end
+
+      def transform_metadata(meta)
+        if meta.sym_type?
+          { meta => true }
+        else
+          # This check is to be able to compare those two hooks:
+          #
+          #   before(:example, :special) { ... }
+          #   before(:example, special: true) { ... }
+          #
+          # In the second case it's a node with a pair that has a value
+          # of a `true_type?`.
+          meta.pairs.map { |pair| { pair.key => transform_true(pair.value) } }
+        end
+      end
+
+      def transform_true(node)
+        node.true_type? ? true : node
+      end
+
       def scope_name
         scope_argument.to_a.first
       end
diff --git a/lib/rubocop/rspec/language.rb b/lib/rubocop/rspec/language.rb
@@ -94,6 +94,18 @@ module Hooks
             append_after
           ]
         )
+
+        module Scopes
+          ALL = SelectorSet.new(
+            %i[
+              each
+              example
+              context
+              all
+              suite
+            ]
+          )
+        end
       end
 
       module Helpers
diff --git a/spec/rubocop/cop/rspec/scattered_setup_spec.rb b/spec/rubocop/cop/rspec/scattered_setup_spec.rb
@@ -38,7 +38,7 @@
     RUBY
   end
 
-  it 'does not flag different hooks' do
+  it 'ignores different hooks' do
     expect_no_offenses(<<-RUBY)
       describe Foo do
         before { bar }
@@ -48,7 +48,7 @@
     RUBY
   end
 
-  it 'does not flag different hook types' do
+  it 'ignores different hook types' do
     expect_no_offenses(<<-RUBY)
       describe Foo do
         before { bar }
@@ -58,7 +58,7 @@
     RUBY
   end
 
-  it 'does not flag hooks in different example groups' do
+  it 'ignores hooks in different example groups' do
     expect_no_offenses(<<-RUBY)
       describe Foo do
         before { bar }
@@ -70,7 +70,7 @@
     RUBY
   end
 
-  it 'does not flag hooks in different shared contexts' do
+  it 'ignores hooks in different shared contexts' do
     expect_no_offenses(<<-RUBY)
       describe Foo do
         shared_context 'one' do
@@ -84,7 +84,7 @@
     RUBY
   end
 
-  it 'does not flag similar method names inside of examples' do
+  it 'ignores similar method names inside of examples' do
     expect_no_offenses(<<-RUBY)
       describe Foo do
         before { bar }
@@ -95,4 +95,29 @@
       end
     RUBY
   end
+
+  it 'ignores hooks with different metadata' do
+    expect_no_offenses(<<-RUBY)
+      describe Foo do
+        before(:example) { foo }
+        before(:example, :special_case) { bar }
+      end
+    RUBY
+  end
+
+  it 'flags hooks with similar metadata' do
+    expect_offense(<<-RUBY)
+      describe Foo do
+        before(:each, :special_case) { foo }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not define multiple hooks in the same example group.
+        before(:example, :special_case) { bar }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not define multiple hooks in the same example group.
+        before(:example, special_case: true) { bar }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not define multiple hooks in the same example group.
+        before(special_case: true) { bar }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not define multiple hooks in the same example group.
+        before(:example, special_case: false) { bar }
+      end
+    RUBY
+  end
 end
diff --git a/spec/rubocop/rspec/hook_spec.rb b/spec/rubocop/rspec/hook_spec.rb
@@ -11,43 +11,86 @@ def hook(source)
     expect(hook('around(:each) { }').name).to be(:around)
   end
 
-  it 'does not break if a hook is not given a symbol literal' do
-    expect(hook('before(scope) { example_setup }').knowable_scope?).to be(false)
-  end
+  describe '#knowable_scope?' do
+    it 'does not break if a hook is not given a symbol literal' do
+      expect(hook('before(scope) { example_setup }').knowable_scope?)
+        .to be(false)
+    end
 
-  it 'knows the scope of a hook with a symbol literal' do
-    expect(hook('before { example_setup }').knowable_scope?).to be(true)
-  end
+    it 'knows the scope of a hook with a symbol literal' do
+      expect(hook('before(:example) { example_setup }').knowable_scope?)
+        .to be(true)
+    end
 
-  it 'ignores other arguments to hooks' do
-    expect(hook('before(:each, :metadata) { example_setup }').scope)
-      .to be(:each)
-  end
+    it 'knows the scope of a hook with no argument' do
+      expect(hook('before { example_setup }').knowable_scope?)
+        .to be(true)
+    end
 
-  it 'classifies nonstandard hook arguments as invalid' do
-    expect(hook('before(:nothing) { example_setup }').valid_scope?).to be(false)
+    it 'knows the scope of a hook with hash metadata' do
+      expect(hook('before(special: true) { example_setup }').knowable_scope?)
+        .to be(true)
+    end
   end
 
-  it 'classifies :each as a valid hook argument' do
-    expect(hook('before(:each) { example_setup }').valid_scope?).to be(true)
-  end
+  describe '#scope' do
+    it 'ignores other arguments to hooks' do
+      expect(hook('before(:each, :metadata) { example_setup }').scope)
+        .to be(:each)
+    end
 
-  it 'classifies :each as an example hook' do
-    expect(hook('before(:each) { }').example?).to be(true)
-  end
+    it 'classifies :each as an example hook' do
+      expect(hook('before(:each) { }').example?).to be(true)
+    end
+
+    it 'defaults to example hook with hash metadata' do
+      expect(hook('before(special: true) { }').example?).to be(true)
+    end
 
-  shared_examples 'standardizes scope' do |source, scope|
-    it "interprets #{source} as having scope #{scope}" do
-      expect(hook(source).scope).to equal(scope)
+    shared_examples 'standardizes scope' do |source, scope|
+      it "interprets #{source} as having scope #{scope}" do
+        expect(hook(source).scope).to equal(scope)
+      end
     end
+
+    include_examples 'standardizes scope', 'before(:each) { }',    :each
+    include_examples 'standardizes scope', 'around(:example) { }', :each
+    include_examples 'standardizes scope', 'after { }',            :each
+
+    include_examples 'standardizes scope', 'before(:all) { }',     :context
+    include_examples 'standardizes scope', 'around(:context) { }', :context
+
+    include_examples 'standardizes scope', 'after(:suite) { }', :suite
   end
 
-  include_examples 'standardizes scope', 'before(:each) { }',    :each
-  include_examples 'standardizes scope', 'around(:example) { }', :each
-  include_examples 'standardizes scope', 'after { }',            :each
+  describe '#metadata' do
+    def metadata(source)
+      hook(source).metadata.to_s
+    end
 
-  include_examples 'standardizes scope', 'before(:all) { }',     :context
-  include_examples 'standardizes scope', 'around(:context) { }', :context
+    it 'extracts symbol metadata' do
+      expect(metadata('before(:example, :special) { foo }'))
+        .to eq('{s(:sym, :special)=>true}')
+    end
+
+    it 'extracts hash metadata' do
+      expect(metadata('before(:example, special: true) { foo }'))
+        .to eq('{s(:sym, :special)=>true}')
+    end
 
-  include_examples 'standardizes scope', 'after(:suite) { }', :suite
+    it 'combines symbol and hash metadata' do
+      expect(metadata('before(:example, :symbol, special: true) { foo }'))
+        .to eq('{s(:sym, :symbol)=>true, s(:sym, :special)=>true}')
+    end
+
+    it 'extracts hash metadata with no scope given' do
+      expect(metadata('before(special: true) { foo }'))
+        .to eq('{s(:sym, :special)=>true}')
+    end
+
+    it 'withstands no arguments' do
+      expect(metadata('before { foo }'))
+        .to be_empty
+    end
+  end
 end
