From 1ec40e312d9f110da80f89bf3403c314e620b80f Mon Sep 17 00:00:00 2001
From: Thomas Noe <2mas@hey.com>
Date: Sat, 19 Mar 2022 18:52:46 -0600
Subject: [PATCH] Add VerifiedDoubleReference cop

---
 CHANGELOG.md                                  |   2 +
 config/default.yml                            |  10 ++
 docs/modules/ROOT/pages/cops.adoc             |   1 +
 docs/modules/ROOT/pages/cops_rspec.adoc       |  75 ++++++++++++
 .../cop/rspec/verified_double_reference.rb    | 111 ++++++++++++++++++
 lib/rubocop/cop/rspec_cops.rb                 |   1 +
 .../rspec/verified_double_reference_spec.rb   |  82 +++++++++++++
 7 files changed, 282 insertions(+)
 create mode 100644 lib/rubocop/cop/rspec/verified_double_reference.rb
 create mode 100644 spec/rubocop/cop/rspec/verified_double_reference_spec.rb

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8035553f0..562474353 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Changelog
 
 ## Master (Unreleased)
+* Add `RSpec/VerifiedDoubleReference` cop. ([@t3h2mas][])
 
 * Fix a false positive for `RSpec/EmptyExampleGroup` when expectations in case statement. ([@ydah][])
 
@@ -675,3 +676,4 @@ Compatibility release so users can upgrade RuboCop to 0.51.0. No new features.
 [@harry-graham]: https://github.com/harry-graham
 [@oshiro3]: https://github.com/oshiro3
 [@ydah]: https://github.com/ydah
+[@t3h2mas]: https://github.com/t3h2mas
diff --git a/config/default.yml b/config/default.yml
index 4db941ebc..89a507887 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -761,6 +761,16 @@ RSpec/VariableName:
   VersionChanged: '1.43'
   Reference: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/VariableName
 
+RSpec/VerifiedDoubleReference:
+  Description: Checks for consistent verified double reference style.
+  Enabled: pending
+  EnforcedStyle: constant
+  SupportedStyles:
+    - constant
+    - string
+  VersionAdded: 2.10.0
+  Reference: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/VerifiedDoubleReference
+
 RSpec/VerifiedDoubles:
   Description: Prefer using verifying doubles over normal doubles.
   Enabled: true
diff --git a/docs/modules/ROOT/pages/cops.adoc b/docs/modules/ROOT/pages/cops.adoc
index 1b978708e..05a4127e8 100644
--- a/docs/modules/ROOT/pages/cops.adoc
+++ b/docs/modules/ROOT/pages/cops.adoc
@@ -83,6 +83,7 @@
 * xref:cops_rspec.adoc#rspecunspecifiedexception[RSpec/UnspecifiedException]
 * xref:cops_rspec.adoc#rspecvariabledefinition[RSpec/VariableDefinition]
 * xref:cops_rspec.adoc#rspecvariablename[RSpec/VariableName]
+* xref:cops_rspec.adoc#rspecverifieddoublereference[RSpec/VerifiedDoubleReference]
 * xref:cops_rspec.adoc#rspecverifieddoubles[RSpec/VerifiedDoubles]
 * xref:cops_rspec.adoc#rspecvoidexpect[RSpec/VoidExpect]
 * xref:cops_rspec.adoc#rspecyield[RSpec/Yield]
diff --git a/docs/modules/ROOT/pages/cops_rspec.adoc b/docs/modules/ROOT/pages/cops_rspec.adoc
index fc4be0231..fb19a5fd0 100644
--- a/docs/modules/ROOT/pages/cops_rspec.adoc
+++ b/docs/modules/ROOT/pages/cops_rspec.adoc
@@ -4300,6 +4300,81 @@ let(:userFood_2) { 'fettuccine' }
 
 * https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/VariableName
 
+== RSpec/VerifiedDoubleReference
+
+|===
+| Enabled by default | Safe | Supports autocorrection | Version Added | Version Changed
+
+| Pending
+| Yes
+| Yes
+| 2.10.0
+| -
+|===
+
+Checks for consistent verified double reference style.
+
+Only investigates references that are one of the supported styles.
+
+This cop can be configured in your configuration using the
+`EnforcedStyle` option and supports `--auto-gen-config`.
+
+=== Examples
+
+==== `EnforcedStyle: constant` (default)
+
+[source,ruby]
+----
+# bad
+let(:foo) do
+  instance_double('ClassName', method_name: 'returned_value')
+end
+
+# good
+let(:foo) do
+  instance_double(ClassName, method_name: 'returned_value')
+end
+----
+
+==== `EnforcedStyle: string`
+
+[source,ruby]
+----
+# bad
+let(:foo) do
+  instance_double(ClassName, method_name: 'returned_value')
+end
+
+# good
+let(:foo) do
+  instance_double('ClassName', method_name: 'returned_value')
+end
+----
+
+==== Reference is not in the supported style list. No enforcement
+
+[source,ruby]
+----
+# good
+let(:foo) do
+  instance_double(@klass, method_name: 'returned_value')
+end
+----
+
+=== Configurable attributes
+
+|===
+| Name | Default value | Configurable values
+
+| EnforcedStyle
+| `constant`
+| `constant`, `string`
+|===
+
+=== References
+
+* https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/VerifiedDoubleReference
+
 == RSpec/VerifiedDoubles
 
 |===
diff --git a/lib/rubocop/cop/rspec/verified_double_reference.rb b/lib/rubocop/cop/rspec/verified_double_reference.rb
new file mode 100644
index 000000000..7d15199f5
--- /dev/null
+++ b/lib/rubocop/cop/rspec/verified_double_reference.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module RSpec
+      # Checks for consistent verified double reference style.
+      #
+      # Only investigates references that are one of the supported styles.
+      #
+      # @see https://relishapp.com/rspec/rspec-mocks/docs/verifying-doubles
+      #
+      # This cop can be configured in your configuration using the
+      # `EnforcedStyle` option and supports `--auto-gen-config`.
+      #
+      # @example `EnforcedStyle: constant` (default)
+      #   # bad
+      #   let(:foo) do
+      #     instance_double('ClassName', method_name: 'returned_value')
+      #   end
+      #
+      #   # good
+      #   let(:foo) do
+      #     instance_double(ClassName, method_name: 'returned_value')
+      #   end
+      #
+      # @example `EnforcedStyle: string`
+      #   # bad
+      #   let(:foo) do
+      #     instance_double(ClassName, method_name: 'returned_value')
+      #   end
+      #
+      #   # good
+      #   let(:foo) do
+      #     instance_double('ClassName', method_name: 'returned_value')
+      #   end
+      #
+      # @example Reference is not in the supported style list. No enforcement
+      #
+      #   # good
+      #   let(:foo) do
+      #     instance_double(@klass, method_name: 'returned_value')
+      #   end
+      class VerifiedDoubleReference < Base
+        extend AutoCorrector
+        include ConfigurableEnforcedStyle
+
+        MSG = 'Use a %<style>s class reference for verified doubles.'
+
+        RESTRICT_ON_SEND = Set[
+          :class_double,
+          :class_spy,
+          :instance_double,
+          :instance_spy,
+          :mock_model,
+          :object_double,
+          :object_spy,
+          :stub_model
+        ].freeze
+
+        REFERENCE_TYPE_STYLES = {
+          str: :string,
+          const: :constant
+        }.freeze
+
+        # @!method verified_double(node)
+        def_node_matcher :verified_double, <<~PATTERN
+          (send
+            nil?
+            RESTRICT_ON_SEND
+            $_class_reference
+            ...)
+        PATTERN
+
+        def on_send(node)
+          verified_double(node) do |class_reference|
+            break correct_style_detected unless opposing_style?(class_reference)
+
+            message = format(MSG, style: style)
+            expression = class_reference.loc.expression
+
+            add_offense(expression, message: message) do |corrector|
+              violation = class_reference.children.last.to_s
+              corrector.replace(expression, correct_style(violation))
+
+              opposite_style_detected
+            end
+          end
+        end
+
+        private
+
+        def opposing_style?(class_reference)
+          class_reference_style = REFERENCE_TYPE_STYLES[class_reference.type]
+
+          # Only enforce supported styles
+          return false unless class_reference_style
+
+          class_reference_style != style
+        end
+
+        def correct_style(violation)
+          if style == :string
+            "'#{violation}'"
+          else
+            violation
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/rubocop/cop/rspec_cops.rb b/lib/rubocop/cop/rspec_cops.rb
index 580176a20..cd92e203e 100644
--- a/lib/rubocop/cop/rspec_cops.rb
+++ b/lib/rubocop/cop/rspec_cops.rb
@@ -97,6 +97,7 @@
 require_relative 'rspec/unspecified_exception'
 require_relative 'rspec/variable_definition'
 require_relative 'rspec/variable_name'
+require_relative 'rspec/verified_double_reference'
 require_relative 'rspec/verified_doubles'
 require_relative 'rspec/void_expect'
 require_relative 'rspec/yield'
diff --git a/spec/rubocop/cop/rspec/verified_double_reference_spec.rb b/spec/rubocop/cop/rspec/verified_double_reference_spec.rb
new file mode 100644
index 000000000..1f7625c09
--- /dev/null
+++ b/spec/rubocop/cop/rspec/verified_double_reference_spec.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::RSpec::VerifiedDoubleReference do
+  verified_doubles = %w[
+    class_double
+    class_spy
+    instance_double
+    instance_spy
+    mock_model
+    object_double
+    object_spy
+    stub_model
+  ]
+
+  verified_doubles.each do |verified_double|
+    describe verified_double do
+      context 'when EnforcedStyle is constant' do
+        let(:cop_config) do
+          { 'EnforcedStyle' => 'constant' }
+        end
+
+        it 'does not flag a violation when using a constant reference' do
+          expect_no_offenses("#{verified_double}(ClassName)")
+        end
+
+        it 'flags a violation when using a string reference' do
+          expect_offense(<<~RUBY, verified_double: verified_double)
+            %{verified_double}('ClassName')
+            _{verified_double} ^^^^^^^^^^^ Use a constant class reference for verified doubles.
+          RUBY
+
+          expect_correction(<<~RUBY)
+            #{verified_double}(ClassName)
+          RUBY
+        end
+
+        include_examples 'detects style',
+                         "#{verified_double}(ClassName)",
+                         'constant'
+      end
+
+      context 'when EnforcedStyle is string' do
+        let(:cop_config) do
+          { 'EnforcedStyle' => 'string' }
+        end
+
+        it 'does not flag a violation when using a string reference' do
+          expect_no_offenses("#{verified_double}('ClassName')")
+        end
+
+        it 'flags a violation when using a constant reference' do
+          expect_offense(<<~RUBY, verified_double: verified_double)
+            %{verified_double}(ClassName)
+            _{verified_double} ^^^^^^^^^ Use a string class reference for verified doubles.
+          RUBY
+
+          expect_correction(<<~RUBY)
+            #{verified_double}('ClassName')
+          RUBY
+        end
+
+        include_examples 'detects style',
+                         "#{verified_double}('ClassName')",
+                         'string'
+      end
+    end
+  end
+
+  it 'does not flag a violation when reference is not a supported style' do
+    expect_no_offenses(<<~RUBY)
+      klass = Array
+      instance_double(klass)
+
+      @sut = Array
+      let(:double) { instance_double(@sut) }
+
+      object_double([])
+
+      class_double(:Model)
+    RUBY
+  end
+end