Add ability to filter hooks via simple keys.

Author: Tim Mertens

features/hooks/filtering.feature

@@ -244,3 +244,42 @@ Feature: filters
       .after context
       """
 
+  Scenario: Filtering hooks using symbols
+    Given a file named "filter_example_hooks_with_symbol_spec.rb" with:
+      """ruby
+      RSpec.configure do |config|
+        config.before(:example, :foo) do
+          invoked_hooks << :before_example_foo_bar
+        end
+      end
+
+      RSpec.describe "a filtered before :example hook" do
+        let(:invoked_hooks) { [] }
+
+        describe "group without a matching metadata key" do
+          it "does not run the hook" do
+            expect(invoked_hooks).to be_empty
+          end
+
+          it "does not run the hook for an example with metadata hash containing the key with a falsey value", :foo => nil do
+            expect(invoked_hooks).to be_empty
+          end
+
+          it "runs the hook for an example with metadata hash containing the key with a truthy value", :foo => :bar do
+            expect(invoked_hooks).to eq([:before_example_foo_bar])
+          end
+
+          it "runs the hook for an example with only the key defined", :foo do
+            expect(invoked_hooks).to eq([:before_example_foo_bar])
+          end
+        end
+
+        describe "group with matching metadata key", :foo do
+          it "runs the hook" do
+            expect(invoked_hooks).to eq([:before_example_foo_bar])
+          end
+        end
+      end
+      """
+    When I run `rspec filter_example_hooks_with_symbol_spec.rb`
+    Then the examples should all pass

lib/rspec/core/metadata_filter.rb

@@ -15,12 +15,13 @@ def apply?(predicate, filters, metadata)
         # @private
         def filter_applies?(key, value, metadata)
           silence_metadata_example_group_deprecations do
-            return filter_applies_to_any_value?(key, value, metadata) if Array === metadata[key] && !(Proc === value)
             return location_filter_applies?(value, metadata)          if key == :locations
             return id_filter_applies?(value, metadata)                if key == :ids
             return filters_apply?(key, value, metadata)               if Hash === value
 
             return false unless metadata.key?(key)
+            return true if TrueClass === value && !!metadata[key]
+            return filter_applies_to_any_value?(key, value, metadata) if Array === metadata[key] && !(Proc === value)
 
             case value
             when Regexp

spec/rspec/core/metadata_filter_spec.rb

@@ -157,6 +157,11 @@ def filter_applies?(key, value, metadata)
             metadata = { :foo => "words" }
             expect(filter_applies?(:foo, { :bar => /word/ }, metadata)).to be_falsey
           end
+
+          it 'matches when a metadata key is specified without a value and exists in the metadata hash' do
+            metadata = { :foo => "words" }
+            expect(filter_applies?(:foo, true, metadata)).to be_truthy
+          end
         end
 
         context "with an Array" do
@@ -199,6 +204,10 @@ def filter_applies?(key, value, metadata)
           it "does not match a proc that evaluates to false" do
             expect(filter_applies?(:tag, lambda { |values| values.include? 'nothing' }, metadata_with_array)).to be_falsey
           end
+
+          it 'matches when a metadata key is specified without a value and exists in the metadata hash' do
+            expect(filter_applies?(:tag, true, metadata_with_array)).to be_truthy
+          end
         end
       end
     end