Include the original test name in expired stub error messages

It is currently very hard to track down such leaked stubs, when
they happen, as they might be created in one test and cause an
exception dozens of tests later.

By including the name of the test that invalidated them, it makes
the debugging process a bit easier.

Note, I made `setup` also accept the current test instance purely
for consistency with `teardown` but it's not strictly necessary.

lib/mocha/hooks.rb

@@ -35,8 +35,14 @@ def mocha_verify(assertion_counter = nil)
     # Resets Mocha after a test (only for use by authors of test libraries).
     #
     # This method should be called after each individual test has finished (including after any "teardown" code).
-    def mocha_teardown
-      Mockery.teardown
+    def mocha_teardown(origin = mocha_test_name)
+      Mockery.teardown(origin)
+    end
+
+    # Returns a string representing the unit test name, to be included in some Mocha
+    # to help track down potential bugs.
+    def mocha_test_name
+      nil
     end
   end
 end

lib/mocha/integration/minitest/adapter.rb

@@ -46,6 +46,21 @@ def after_teardown
           super
           mocha_teardown
         end
+
+        # @private
+        def mocha_test_name
+          if respond_to?(:name)
+            test_name = name
+          elsif respond_to?(:__name__) # Older minitest
+            test_name = __name__
+          end
+
+          if test_name
+            "#{self.class.name}##{test_name}"
+          else
+            self.class.name
+          end
+        end
       end
     end
   end

lib/mocha/integration/test_unit/adapter.rb

@@ -37,6 +37,11 @@ def self.included(mod)
 
         private
 
+        # @private
+        def mocha_test_name
+          name
+        end
+
         # @private
         def handle_mocha_expectation_error(exception)
           return false unless exception.is_a?(Mocha::ExpectationError)

lib/mocha/mock.rb

@@ -343,8 +343,8 @@ def __verified__?(assertion_counter = nil)
     end
 
     # @private
-    def __expire__
-      @expired = true
+    def __expire__(origin)
+      @expired = origin || true
     end
 
     # @private
@@ -393,8 +393,10 @@ def check_responder_responds_to(symbol)
     def check_expiry
       return unless @expired
 
+      origin = @expired == true ? 'one test' : @expired
+
       sentences = [
-        "#{mocha_inspect} was instantiated in one test but it is receiving invocations within another test.",
+        "#{mocha_inspect} was instantiated in #{origin} but it is receiving invocations within another test.",
         'This can lead to unintended interactions between tests and hence unexpected test failures.',
         'Ensure that every test correctly cleans up any state that it introduces.'
       ]

lib/mocha/mockery.rb

@@ -48,8 +48,8 @@ def verify(*args)
         instance.verify(*args)
       end
 
-      def teardown
-        instance.teardown
+      def teardown(origin = nil)
+        instance.teardown(origin)
       ensure
         @instances.pop
       end
@@ -91,9 +91,9 @@ def verify(assertion_counter = nil)
       end
     end
 
-    def teardown
+    def teardown(origin = nil)
       stubba.unstub_all
-      mocks.each(&:__expire__)
+      mocks.each { |m| m.__expire__(origin) }
       reset
     end
 

test/acceptance/mock_test.rb

@@ -159,7 +159,7 @@ def test_should_raise_stubbing_error_if_mock_receives_invocations_in_another_tes
     reuse_mock_test_result = run_as_test do
       Foo.logger.expects(:log).with('Foo was here')
       e = assert_raises(Mocha::StubbingError) { Foo.new.use_the_mock }
-      assert e.message.include?('#<Mock:Logger> was instantiated in one test but it is receiving invocations within another test.')
+      assert e.message.include?('#<Mock:Logger> was instantiated in FakeTest#test_me but it is receiving invocations within another test.')
       assert e.message.include?('This can lead to unintended interactions between tests and hence unexpected test failures.')
       assert e.message.include?('Ensure that every test correctly cleans up any state that it introduces.')
     end

test/integration/shared_tests.rb

@@ -172,5 +172,37 @@ def test_real_object_expectation_does_not_leak_into_subsequent_test
     assert_equal execution_point, ExecutionPoint.new(exception.backtrace)
     assert_match(/undefined method `foo'/, exception.message)
   end
+
+  def test_leaky_mock
+    origin = nil
+    leaky_mock = nil
+    execution_point = nil
+    test_result = run_as_tests(
+      test_1: lambda {
+        origin = mocha_test_name
+        leaky_mock ||= begin
+          bad_mock = mock(:leaky)
+          bad_mock.expects(:call)
+          bad_mock
+        end
+
+        leaky_mock.call
+      },
+      test_2: lambda {
+        leaky_mock ||= begin
+          bad_mock = mock(:leaky)
+          bad_mock.expects(:call)
+          bad_mock
+        end
+
+        execution_point = ExecutionPoint.current; leaky_mock.call
+      }
+    )
+    assert_errored(test_result)
+    exception = test_result.errors.first.exception
+    assert_equal execution_point, ExecutionPoint.new(exception.backtrace)
+    expected = /#<Mock:leaky> was instantiated in #{Regexp.escape(origin)} but it is receiving invocations within another test/
+    assert_match(expected, exception.message)
+  end
 end
 # rubocop:enable Metrics/ModuleLength

test/test_runner.rb

@@ -7,10 +7,14 @@ def run_as_test(&block)
     run_as_tests(test_me: block)
   end
 
-  # rubocop:disable Metrics/AbcSize
+  # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
   def run_as_tests(methods = {})
     base_class = Mocha::TestCase
     test_class = Class.new(base_class) do
+      def self.name;
+        'FakeTest'
+      end
+
       include Assertions
 
       methods.each do |(method_name, proc)|
@@ -45,7 +49,7 @@ def run_as_tests(methods = {})
 
     test_result
   end
-  # rubocop:enable Metrics/AbcSize
+  # rubocop:enable Metrics/AbcSize, Metrics/MethodLength
 
   def assert_passed(test_result)
     flunk "Test errored unexpectedly with message: #{test_result.errors.map(&:exception)}" if test_result.error_count > 0

test/unit/hooks_test.rb

@@ -14,7 +14,7 @@ class << self
   class FakeMockery
     def verify(*args); end
 
-    def teardown
+    def teardown(_origin = nil)
       raise 'exception within Mockery#teardown'
     end
   end