Fix exact match on ActionController::Parameters

This was broken in this previous commit [1] which was part of #660 and
which was released in v2.4.3.

Previously the only requirement we put on `Hash`-like arguments was that
they respond to `#keys` & `#[]` methods. However, the change in [1] we
introduced an implicit assumption that they also respond to a `#length`
method which is caused the problem described here [2].

However, `ActionController::Parameters` [3] is commonly used in Rails
apps and it does *not* respond to `#length`. So it seems better to add a
guard condition to ensure the object responds to `#keys` and use that to
determine the length.

Note that the `HasEntry`, `HasKey` and `HasKeys` matchers already work
this way and so this feels like it makes `HasEntries` more consistent.

[1]: 5e6a07b
[2]: #662 (comment)
[3]: https://api.rubyonrails.org/classes/ActionController/Parameters.html

lib/mocha/parameter_matchers/has_entries.rb

@@ -39,7 +39,8 @@ def initialize(entries, exact: false)
       def matches?(available_parameters)
         parameter = available_parameters.shift
         return false unless parameter
-        return false if @exact && @entries.length != parameter.length
+        return false unless parameter.respond_to?(:keys)
+        return false if @exact && @entries.length != parameter.keys.length
 
         has_entry_matchers = @entries.map { |key, value| HasEntry.new(key, value) }
         AllOf.new(*has_entry_matchers).matches?([parameter])

test/acceptance/parameter_matcher_test.rb

@@ -1,5 +1,7 @@
 require File.expand_path('../acceptance_test_helper', __FILE__)
 
+require 'hashlike'
+
 class ParameterMatcherTest < Mocha::TestCase
   include AcceptanceTest
 
@@ -20,6 +22,16 @@ def test_should_match_hash_parameter_which_is_exactly_the_same
     assert_passed(test_result)
   end
 
+  def test_should_match_hash_parameter_when_method_invoked_with_hashlike_object_with_no_length_method
+    test_result = run_as_test do
+      mock = mock()
+      hash = { key_1: 'value_1' }
+      mock.expects(:method).with(hash)
+      mock.method(Hashlike.new(key_1: 'value_1'))
+    end
+    assert_passed(test_result)
+  end
+
   def test_should_not_match_hash_parameter_which_is_not_exactly_the_same
     test_result = run_as_test do
       mock = mock()
@@ -38,6 +50,17 @@ def test_should_not_match_hash_parameter_when_method_invoked_with_no_parameters
     assert_failed(test_result)
   end
 
+  def test_should_not_match_hash_parameter_when_method_invoked_with_empty_hashlike_object_with_no_length_method
+    test_result = run_as_test do
+      mock = mock()
+      hash = { key_1: 'value_1' }
+      mock.expects(:method).with(hash)
+      hashlike = Hashlike.new({})
+      mock.method(hashlike)
+    end
+    assert_failed(test_result)
+  end
+
   def test_should_match_hash_parameter_with_specified_key
     test_result = run_as_test do
       mock = mock()

test/unit/parameter_matchers/has_entries_test.rb

@@ -50,6 +50,18 @@ def test_should_not_match_hashlike_object
     assert !matcher.matches?([hashlike])
   end
 
+  def test_should_match_hashlike_object_with_no_length_method_when_exact_match_required
+    matcher = HasEntries.new({ key_1: 'value_1' }, exact: true)
+    hashlike = Hashlike.new(key_1: 'value_1')
+    assert matcher.matches?([hashlike])
+  end
+
+  def test_should_not_match_hashlike_object_with_no_length_method_when_exact_match_required
+    matcher = HasEntries.new({ key_1: 'value_1' }, exact: true)
+    hashlike = Hashlike.new(key_1: 'value_1', key_2: 'value_2')
+    assert !matcher.matches?([hashlike])
+  end
+
   def test_should_describe_matcher
     matcher = has_entries(key_1: 'value_1', key_2: 'value_2')
     description = matcher.mocha_inspect