Using UndefinedValue as a default attribute

Author: skatkov

lib/rspec/rails/matchers/have_reported_error.rb

@@ -3,6 +3,11 @@
 module RSpec
   module Rails
     module Matchers
+      # @api private
+      # Sentinel value to distinguish between no argument passed vs explicitly passed nil.
+      # This follows the same pattern as RSpec's raise_error matcher.
+      UndefinedValue = Object.new.freeze
+
       # @api private
       class ErrorSubscriber
         attr_reader :events
@@ -28,17 +33,20 @@ def report(error, **attrs)
       class HaveReportedError < RSpec::Rails::Matchers::BaseMatcher
         # Initialize the matcher following raise_error patterns
         #
+        # Uses UndefinedValue as default to distinguish between no argument 
+        # passed vs explicitly passed nil (same as raise_error matcher).
+        #
         # @param expected_error_or_message [Class, String, Regexp, nil] 
         #   Error class, message string, or message pattern
         # @param expected_message [String, Regexp, nil] 
         #   Expected message when first param is a class
-        def initialize(expected_error_or_message = nil, expected_message = nil)
+        def initialize(expected_error_or_message = UndefinedValue, expected_message = nil)
           @actual_error = nil
           @attributes = {}
           @error_subscriber = nil
 
           case expected_error_or_message
-          when nil
+          when nil, UndefinedValue
             @expected_error = nil
             @expected_message = expected_message
           when String, Regexp
@@ -232,7 +240,7 @@ def unmatched_attributes(actual)
       #
       # @param expected_error_or_message [Class, String, Regexp, nil] the expected error class, message string, or message pattern
       # @param expected_message [String, Regexp, nil] the expected error message to match
-      def have_reported_error(expected_error_or_message = nil, expected_message = nil)
+      def have_reported_error(expected_error_or_message = UndefinedValue, expected_message = nil)
         HaveReportedError.new(expected_error_or_message, expected_message)
       end
 

spec/rspec/rails/matchers/have_reported_error_spec.rb

@@ -17,12 +17,22 @@ class AnotherTestError < StandardError; end
       expect {Rails.error.report(StandardError.new("test error"))}.to have_reported_error
     end
 
+    it "passes when an error is reported with explicit nil argument" do
+      expect {Rails.error.report(StandardError.new("test error"))}.to have_reported_error(nil)
+    end
+
     it "fails when no errors are reported" do
       expect {
         expect { "no error" }.to have_reported_error
       }.to fail_with(/Expected the block to report an error, but none was reported./)
     end
 
+    it "fails when no errors are reported with explicit nil argument" do
+      expect {
+        expect { "no error" }.to have_reported_error(nil)
+      }.to fail_with(/Expected the block to report an error, but none was reported./)
+    end
+
     it "passes when negated and no errors are reported" do
       expect { "no error" }.not_to have_reported_error
     end