Add new RSpec/IsExpectedSpecify cop

Fix: #1658

.rubocop.yml

@@ -165,6 +165,8 @@ RSpec/IdenticalEqualityAssertion:
   Enabled: true
 RSpec/IndexedLet:
   Enabled: true
+RSpec/IsExpectedSpecify:
+  Enabled: true
 RSpec/MatchArray:
   Enabled: true
 RSpec/MetadataStyle:

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Master (Unreleased)
 
+- Add new `RSpec/IsExpectedSpecify` cop. ([@ydah])
 - Add support for `assert_true` and `assert_false` to `RSpec/Rails/MinitestAssertions`. ([@ydah])
 - Support asserts with messages in `Rspec/BeEmpty`. ([@G-Rath])
 - Add support for `assert_empty`, `assert_not_empty` and `refute_empty` to `RSpec/Rails/MinitestAssertions`. ([@ydah])

config/default.yml

@@ -548,6 +548,13 @@ RSpec/InstanceVariable:
   StyleGuide: https://rspec.rubystyle.guide/#instance-variables
   Reference: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/InstanceVariable
 
+RSpec/IsExpectedSpecify:
+  Description: Check for `specify` with `is_expected` and one-liner expectations.
+  Enabled: pending
+  VersionAdded: "<<next>>"
+  StyleGuide: https://rspec.rubystyle.guide/#it-and-specify
+  Reference: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/IsExpectedSpecify
+
 RSpec/ItBehavesLike:
   Description: Checks that only one `it_behaves_like` style is used.
   Enabled: true

docs/modules/ROOT/pages/cops.adoc

@@ -52,6 +52,7 @@
 * xref:cops_rspec.adoc#rspecindexedlet[RSpec/IndexedLet]
 * xref:cops_rspec.adoc#rspecinstancespy[RSpec/InstanceSpy]
 * xref:cops_rspec.adoc#rspecinstancevariable[RSpec/InstanceVariable]
+* xref:cops_rspec.adoc#rspecisexpectedspecify[RSpec/IsExpectedSpecify]
 * xref:cops_rspec.adoc#rspecitbehaveslike[RSpec/ItBehavesLike]
 * xref:cops_rspec.adoc#rspeciteratedexpectation[RSpec/IteratedExpectation]
 * xref:cops_rspec.adoc#rspecleadingsubject[RSpec/LeadingSubject]

docs/modules/ROOT/pages/cops_rspec.adoc

@@ -2747,6 +2747,42 @@ end
 * https://rspec.rubystyle.guide/#instance-variables
 * https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/InstanceVariable
 
+== RSpec/IsExpectedSpecify
+
+|===
+| Enabled by default | Safe | Supports autocorrection | Version Added | Version Changed
+
+| Pending
+| Yes
+| Yes
+| <<next>>
+| -
+|===
+
+Check for `specify` with `is_expected` and one-liner expectations.
+
+=== Examples
+
+[source,ruby]
+----
+# bad
+specify { is_expected.to be_truthy }
+
+# good
+it { is_expected.to be_truthy }
+
+# good
+specify do
+  # ...
+end
+specify { expect(sqrt(4)).to eq(2) }
+----
+
+=== References
+
+* https://rspec.rubystyle.guide/#it-and-specify
+* https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/IsExpectedSpecify
+
 == RSpec/ItBehavesLike
 
 |===

lib/rubocop/cop/rspec/is_expected_specify.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module RSpec
+      # Check for `specify` with `is_expected` and one-liner expectations.
+      #
+      # @example
+      #   # bad
+      #   specify { is_expected.to be_truthy }
+      #
+      #   # good
+      #   it { is_expected.to be_truthy }
+      #
+      #   # good
+      #   specify do
+      #     # ...
+      #   end
+      #   specify { expect(sqrt(4)).to eq(2) }
+      #
+      class IsExpectedSpecify < Base
+        extend AutoCorrector
+
+        RESTRICT_ON_SEND = %i[specify].freeze
+        IS_EXPECTED_METHODS = ::Set[:is_expected, :are_expected].freeze
+        MSG = 'Use `it` instead of `specify`.'
+
+        # @!method offense?(node)
+        def_node_matcher :offense?, <<~PATTERN
+          (block (send _ :specify) _ (send (send _ IS_EXPECTED_METHODS) ...))
+        PATTERN
+
+        def on_send(node)
+          block_node = node.parent
+          return unless block_node&.single_line? && offense?(block_node)
+
+          selector = node.loc.selector
+          add_offense(selector) do |corrector|
+            corrector.replace(selector, 'it')
+          end
+        end
+      end
+    end
+  end
+end

lib/rubocop/cop/rspec_cops.rb

@@ -78,6 +78,7 @@
 require_relative 'rspec/indexed_let'
 require_relative 'rspec/instance_spy'
 require_relative 'rspec/instance_variable'
+require_relative 'rspec/is_expected_specify'
 require_relative 'rspec/it_behaves_like'
 require_relative 'rspec/iterated_expectation'
 require_relative 'rspec/leading_subject'

spec/rubocop/cop/rspec/is_expected_specify_spec.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::RSpec::IsExpectedSpecify, :config do
+  it 'registers an offense when using `specify` and one-liner style' do
+    expect_offense(<<~RUBY)
+      specify { is_expected.to be_truthy }
+      ^^^^^^^ Use `it` instead of `specify`.
+      specify { are_expected.to be_falsy }
+      ^^^^^^^ Use `it` instead of `specify`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      it { is_expected.to be_truthy }
+      it { are_expected.to be_falsy }
+    RUBY
+  end
+
+  it 'does not register an offense when using `specify` ' \
+     'and not one-liner style' do
+    expect_no_offenses(<<~RUBY)
+      specify { expect(sqrt(4)).to eq(2) }
+    RUBY
+  end
+
+  it 'does not register an offense when using `specify` and multi line' do
+    expect_no_offenses(<<~RUBY)
+      specify do
+        is_expected.to be_truthy
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when using `it` and one-liner style' do
+    expect_no_offenses(<<~RUBY)
+      it { is_expected.to be_truthy }
+    RUBY
+  end
+
+  it 'does not register an offense when using `specify` with metadata' do
+    expect_no_offenses(<<~RUBY)
+      specify "pending", :pending
+    RUBY
+  end
+end