Allow expect_offense to have variables

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New features
 
 * [#6289](https://github.com/rubocop-hq/rubocop/issues/6289): Add new `CheckDefinitionPathHierarchy` option for `Naming/FileName`. ([@jschneid][])
+* [#8069](https://github.com/rubocop-hq/rubocop/issues/8069): New option for `expect_offense` to help format offense templates. ([@marcandre][])
 
 ### Bug fixes
 

lib/rubocop/rspec/expect_offense.rb

@@ -71,9 +71,27 @@ module RSpec
     #   RUBY
     #
     #   expect_no_corrections
+    #
+    # If your code has variables of different lengths, you can use `%{foo}`
+    # and `^{foo}` to format your template:
+    #
+    #   %w[raise fail].each do |keyword|
+    #     expect_offense(<<~RUBY, keyword: keyword)
+    #       %{keyword}(RuntimeError, msg)
+    #       ^{keyword}^^^^^^^^^^^^^^^^^^^ Redundant `RuntimeError` argument can be removed.
+    #     RUBY
     module ExpectOffense
+      def format_offense(source, **replacements)
+        replacements.each do |keyword, value|
+          source = source.gsub("%{#{keyword}}", value)
+                         .gsub("^{#{keyword}}", '^' * value.size)
+        end
+        source
+      end
+
       # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
-      def expect_offense(source, file = nil)
+      def expect_offense(source, file = nil, **replacements)
+        source = format_offense(source, **replacements)
         RuboCop::Formatter::DisabledConfigFormatter
           .config_to_allow_offenses = {}
         RuboCop::Formatter::DisabledConfigFormatter.detected_styles = {}

spec/rubocop/cop/style/redundant_exception_spec.rb

@@ -5,67 +5,55 @@
 
   shared_examples 'common behavior' do |keyword|
     it "reports an offense for a #{keyword} with RuntimeError" do
-      src = "#{keyword} RuntimeError, msg"
-      inspect_source(src)
-      expect(cop.highlights).to eq([src])
-      expect(cop.messages)
-        .to eq(['Redundant `RuntimeError` argument can be removed.'])
-    end
+      expect_offense(<<~RUBY, keyword: keyword)
+        %{keyword} RuntimeError, msg
+        ^{keyword}^^^^^^^^^^^^^^^^^^ Redundant `RuntimeError` argument can be removed.
+      RUBY
 
-    it "reports an offense for a #{keyword} with RuntimeError.new" do
-      src = "#{keyword} RuntimeError.new(msg)"
-      inspect_source(src)
-      expect(cop.highlights).to eq([src])
-      expect(cop.messages)
-        .to eq(['Redundant `RuntimeError.new` call can be replaced with ' \
-                'just the message.'])
+      expect_correction(<<~RUBY)
+        #{keyword} msg
+      RUBY
     end
 
-    it "accepts a #{keyword} with RuntimeError if it does not have 2 args" do
-      expect_no_offenses("#{keyword} RuntimeError, msg, caller")
-    end
+    it "reports an offense for a #{keyword} with RuntimeError and ()" do
+      expect_offense(<<~RUBY, keyword: keyword)
+        %{keyword}(RuntimeError, msg)
+        ^{keyword}^^^^^^^^^^^^^^^^^^^ Redundant `RuntimeError` argument can be removed.
+      RUBY
 
-    it "auto-corrects a #{keyword} RuntimeError by removing RuntimeError" do
-      src = "#{keyword} RuntimeError, msg"
-      result_src = "#{keyword} msg"
-      new_src = autocorrect_source(src)
-      expect(new_src).to eq(result_src)
+      expect_correction(<<~RUBY)
+        #{keyword}(msg)
+      RUBY
     end
 
-    it "auto-corrects a #{keyword} RuntimeError and leaves parentheses" do
-      src = "#{keyword}(RuntimeError, msg)"
-      result_src = "#{keyword}(msg)"
-      new_src = autocorrect_source(src)
-      expect(new_src).to eq(result_src)
-    end
+    it "reports an offense for a #{keyword} with RuntimeError.new" do
+      expect_offense(<<~RUBY, keyword: keyword)
+        %{keyword} RuntimeError.new msg
+        ^{keyword}^^^^^^^^^^^^^^^^^^^^^ Redundant `RuntimeError.new` call can be replaced with just the message.
+      RUBY
 
-    it "auto-corrects a #{keyword} RuntimeError.new with parentheses by " \
-       'removing RuntimeError.new' do
-      src = "#{keyword} RuntimeError.new(msg)"
-      result_src = "#{keyword} msg"
-      new_src = autocorrect_source(src)
-      expect(new_src).to eq(result_src)
+      expect_correction(<<~RUBY)
+        #{keyword} msg
+      RUBY
     end
 
-    it "auto-corrects a #{keyword} RuntimeError.new without parentheses by " \
-       'removing RuntimeError.new' do
-      src = "#{keyword} RuntimeError.new msg"
-      result_src = "#{keyword} msg"
-      new_src = autocorrect_source(src)
-      expect(new_src).to eq(result_src)
+    it "reports an offense for a #{keyword} with RuntimeError.new" do
+      expect_offense(<<~RUBY, keyword: keyword)
+        %{keyword} RuntimeError.new(msg)
+        ^{keyword}^^^^^^^^^^^^^^^^^^^^^^ Redundant `RuntimeError.new` call can be replaced with just the message.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        #{keyword} msg
+      RUBY
     end
 
-    it "does not modify #{keyword} w/ RuntimeError if it does not have 2 " \
-       'args' do
-      src = "#{keyword} runtimeError, msg, caller"
-      new_src = autocorrect_source(src)
-      expect(new_src).to eq(src)
+    it "accepts a #{keyword} with RuntimeError if it does not have 2 args" do
+      expect_no_offenses("#{keyword} RuntimeError, msg, caller")
     end
 
-    it 'does not modify rescue w/ non redundant error' do
-      src = "#{keyword} OtherError, msg"
-      new_src = autocorrect_source(src)
-      expect(new_src).to eq(src)
+    it 'accepts rescue w/ non redundant error' do
+      expect_no_offenses "#{keyword} OtherError, msg"
     end
   end