Fail fast if invocation matches never expectation

Previously when an invocation matched an expectation which did not allow
invocations (i.e. `Expectation#never` had been called on it), but the
invocation also matched another expectation which did allow invocations,
then the test would not fail with an unexpected invocation error.

After #681 a deprecation warning was displayed in this scenario, but now
an unexpected invocation error is reported.

This behaviour was confusing and had led to a number of issues being
raised over the years: #44, #131, #490 & most recently #678. Previously
I had thought this was a symptom of the JMock v1 dispatch behaviour
(which _might_ still be true) and thus would be best addressed by
adopting the JMock v2 dispatch behaviour (#173). However, having
considered this specific scenario involving a "never" expectation, I've
decided to try to fix it with the changes in this commit.

Also the new behaviour will bring the behaviour into line with what is
already the case for mocks where `Mock#stub_everything` has been called
as per this acceptance test [1] that was introduced in this commit [2].

Now a test like this will fail with an unexpected invocation error:

    mock = mock('mock')
    mock.stubs(:method)
    mock.expects(:method).never
    mock.method

    unexpected invocation: #<Mock:mock>.method()
    unsatisfied expectations:
    - expected never, invoked once: #<Mock:mock>.method(any_parameters)
    satisfied expectations:
    - allowed any number of times, invoked never: #<Mock:mock>.method(any_parameters)

This commit also takes into account the fix in this commit [3]: In #681
I added logic to display a deprecation warning about a change I planned
to make in this PR. However, it turns out the logic in both was faulty
as demonstrated in this example [4] where the deprecation warning was
incorrectly displayed for the 2nd call to `Foo.create_if`:

    class Foo
      def self.create_if(condition)
        new if condition
      end
    end

    test "it creates only if condition is true" do
      Foo.expects(:new).never
      Foo.create_if(false)

      Foo.expects(:new).once
      Foo.create_if(true)
    end

This commit adds a new acceptance test to cover an example where the
logic was incorrect and updates the logic in `Mock#handle_method_call`
to fix the logic so this new test passes and none of the existing tests
fail. Unfortunately the implementation is now rather complicated and
hard to follow, but I think it will do for now. I have a couple of ideas
for ways to simplify it, but I don't have time to work on that now.

Closes #678. Also addresses #490, #131 & #44.

[1]: https://github.com/freerange/mocha/blob/f2fa99197f35e2d2ce9554db63f6964057e29ce0/test/acceptance/expected_invocation_count_test.rb#L202-L214
[2]: d358377
[3]: 01874f1
[4]: #679 (comment)

README.md

@@ -276,7 +276,7 @@ Maybe, but probably not. Partial mocking changes the state of objects in the `Ob
 
 Stubs and expectations are basically the same thing. A stub is just an expectation of zero or more invocations. The `Expectation#stubs` method is syntactic sugar to make the intent of the test more explicit.
 
-When a method is invoked on a mock object, the mock object searches through its expectations from newest to oldest to find one that matches the invocation. After the invocation, the matching expectation might stop matching further invocations.
+When a method is invoked on a mock object, the mock object searches through its expectations from newest to oldest to find one that matches the invocation. After the invocation, the matching expectation might stop matching further invocations. If the expectation that matches the invocation has a cardinality of "never", then an unexpected invocation error is reported.
 
 See the [documentation](https://mocha.jamesmead.org/Mocha/Mock.html) for `Mocha::Mock` for further details.
 

lib/mocha/mock.rb

@@ -35,6 +35,9 @@ module Mocha
   # while an +expects(:foo).at_least_once+ expectation will always be matched
   # against invocations.
   #
+  # However, note that if the expectation that matches the invocation has a
+  # cardinality of "never", then an unexpected invocation error is reported.
+  #
   # This scheme allows you to:
   #
   # - Set up default stubs in your the +setup+ method of your test class and
@@ -326,15 +329,11 @@ def handle_method_call(symbol, arguments, block) # rubocop:disable Metrics/Cyclo
       matching_expectations = all_expectations.matching_expectations(invocation)
 
       index = 0
-      never_allowed_expectation = nil
       while index < matching_expectations.length
         matching_expectation = matching_expectations[index]
         if matching_expectation.invocations_never_allowed?
-          never_allowed_expectation = matching_expectation
+          raise_unexpected_invocation_error(invocation, matching_expectation)
         elsif matching_expectation.invocations_allowed?
-          if never_allowed_expectation
-            invocation_not_allowed_warning(invocation, never_allowed_expectation)
-          end
           return matching_expectation.invoke(invocation)
         end
         index += 1
@@ -387,14 +386,6 @@ def any_expectations?
 
     private
 
-    def invocation_not_allowed_warning(invocation, expectation)
-      messages = [
-        "The expectation defined at #{expectation.definition_location} does not allow invocations, but #{invocation.call_description} was invoked.",
-        'This invocation will cause the test to fail fast in a future version of Mocha.'
-      ]
-      Deprecation.warning(messages.join(' '))
-    end
-
     def raise_unexpected_invocation_error(invocation, matching_expectation)
       if @unexpected_invocation.nil?
         @unexpected_invocation = invocation

test/acceptance/mocked_methods_dispatch_test.rb

@@ -1,6 +1,4 @@
 require File.expand_path('../acceptance_test_helper', __FILE__)
-require 'deprecation_disabler'
-require 'execution_point'
 
 class MockedMethodDispatchTest < Mocha::TestCase
   include AcceptanceTest
@@ -75,37 +73,30 @@ def test_should_find_latest_expectation_with_range_of_expected_invocation_count_
     assert_passed(test_result)
   end
 
-  def test_should_display_deprecation_warning_if_invocation_matches_expectation_with_never_cardinality
-    execution_point = nil
+  def test_should_fail_fast_if_invocation_matches_expectation_with_never_cardinality
     test_result = run_as_test do
       mock = mock('mock')
       mock.stubs(:method)
-      mock.expects(:method).never; execution_point = ExecutionPoint.current
-      DeprecationDisabler.disable_deprecations do
-        mock.method
-      end
+      mock.expects(:method).never
+      mock.method
     end
-    assert_passed(test_result)
-    message = Mocha::Deprecation.messages.last
-    location = execution_point.location
-    expected = [
-      "The expectation defined at #{location} does not allow invocations, but #<Mock:mock>.method() was invoked.",
-      'This invocation will cause the test to fail fast in a future version of Mocha.'
-    ]
-    assert_equal expected.join(' '), message
+    assert_failed(test_result)
+    assert_equal [
+      'unexpected invocation: #<Mock:mock>.method()',
+      'unsatisfied expectations:',
+      '- expected never, invoked once: #<Mock:mock>.method(any_parameters)',
+      'satisfied expectations:',
+      '- allowed any number of times, invoked never: #<Mock:mock>.method(any_parameters)'
+    ], test_result.failure_message_lines
   end
 
-  def test_should_not_display_deprecation_warning_if_invocation_matches_expectation_allowing_invocation_before_matching_expectation_with_never_cardinality
+  def test_should_not_fail_fast_if_invocation_matches_expectation_allowing_invocation_before_matching_expectation_with_never_cardinality
     test_result = run_as_test do
       mock = mock('mock')
       mock.expects(:method).never
       mock.expects(:method).once
-      Mocha::Deprecation.messages = []
-      DeprecationDisabler.disable_deprecations do
-        mock.method
-      end
+      mock.method
     end
     assert_passed(test_result)
-    assert Mocha::Deprecation.messages.empty?
   end
 end