class Mocha::Configuration
This class allows you to determine what should happen under certain circumstances. In each scenario, Mocha
can be configured to {.allow do nothing}, {.warn_when display a warning message}, or {.prevent raise an exception}. The relevant scenario is identified using one of the following symbols:
-
:stubbing_method_unnecessarily
This is useful for identifying unused stubs. Unused stubs are often accidentally introduced when code is {martinfowler.com/bliki/DefinitionOfRefactoring.html refactored}. Allowed by default. -
:stubbing_non_existent_method
- This is useful if you want to ensure that methods you're mocking really exist. A common criticism of unit tests with mock objects is that such a test may (incorrectly) pass when an equivalent non-mocking test would (correctly) fail. While you should always have some integration tests, particularly for critical business functionality, thisMocha
configuration setting should catch scenarios when mocked methods and real methods have become misaligned. Allowed by default. -
:stubbing_non_public_method
- Many people think that it's good practice only to mock public methods. This is one way to prevent your tests being too tightly coupled to the internal implementation of a class. Such tests tend to be very brittle and not much use when refactoring. Allowed by default. -
:stubbing_method_on_non_mock_object
- If you like the idea of {www.jmock.org/oopsla2004.pdf mocking roles not objects} and {www.mockobjects.com/2007/04/test-smell-mocking-concrete-classes.html you don't like stubbing concrete classes}, this is the setting for you. However, while this restriction makes a lot of sense in Java with its {java.sun.com/docs/books/tutorial/java/concepts/interface.html explicit interfaces}, it may be moot in Ruby where roles are probably best represented as Modules. Allowed by default. -
:stubbing_method_on_nil
- This is usually done accidentally, but there might be rare cases where it is intended. Prevented by default.
@example Preventing unnecessary stubbing of a method
Mocha::Configuration.prevent(:stubbing_method_unnecessarily) example = mock('example') example.stubs(:unused_stub) # => Mocha::StubbingError: stubbing method unnecessarily: # => #<Mock:example>.unused_stub(any_parameters)
@example Preventing stubbing of a method on a non-mock object
Mocha::Configuration.prevent(:stubbing_method_on_non_mock_object) class Example def example_method; end end example = Example.new example.stubs(:example_method) # => Mocha::StubbingError: stubbing method on non-mock object: # => #<Example:0x593620>.example_method
@example Preventing stubbing of a non-existent method
Mocha::Configuration.prevent(:stubbing_non_existent_method) class Example end example = Example.new example.stubs(:method_that_doesnt_exist) # => Mocha::StubbingError: stubbing non-existent method: # => #<Example:0x593760>.method_that_doesnt_exist
@example Preventing stubbing of a non-public method
Mocha::Configuration.prevent(:stubbing_non_public_method) class Example def internal_method; end private :internal_method end example = Example.new example.stubs(:internal_method) # => Mocha::StubbingError: stubbing non-public method: # => #<Example:0x593530>.internal_method
Typically the configuration would be set globally in a test_helper.rb
or spec_helper.rb
file. However, it can also be temporarily overridden locally using the block syntax of the relevant method. In the latter case, the original configuration settings are restored when the block is exited.
@example Temporarily allowing stubbing of a non-existent method
Mocha::Configuration.prevent(:stubbing_non_public_method) class Example end Mocha::Configuration.allow(:stubbing_non_existent_method) do example = Example.new example.stubs(:method_that_doesnt_exist) # => no exception raised end
Constants
- DEFAULTS
Public Class Methods
Allow the specified action
.
@param [Symbol] action one of :stubbing_method_unnecessarily
, :stubbing_method_on_non_mock_object
, :stubbing_non_existent_method
, :stubbing_non_public_method
, :stubbing_method_on_nil
. @yield optional block during which the configuration change will be changed before being returned to its original value at the end of the block.
# File lib/mocha/configuration.rb, line 82 def allow(action, &block) change_config action, :allow, &block end
@private
# File lib/mocha/configuration.rb, line 87 def allow?(action) configuration[action] == :allow end
Raise a {StubbingError} if if the specified action
is attempted.
@param [Symbol] action one of :stubbing_method_unnecessarily
, :stubbing_method_on_non_mock_object
, :stubbing_non_existent_method
, :stubbing_non_public_method
, :stubbing_method_on_nil
. @yield optional block during which the configuration change will be changed before being returned to its original value at the end of the block.
# File lib/mocha/configuration.rb, line 108 def prevent(action, &block) change_config action, :prevent, &block end
@private
# File lib/mocha/configuration.rb, line 113 def prevent?(action) configuration[action] == :prevent end
@private
# File lib/mocha/configuration.rb, line 118 def reset_configuration @configuration = nil end
Warn if the specified action
is attempted.
@param [Symbol] action one of :stubbing_method_unnecessarily
, :stubbing_method_on_non_mock_object
, :stubbing_non_existent_method
, :stubbing_non_public_method
, :stubbing_method_on_nil
. @yield optional block during which the configuration change will be changed before being returned to its original value at the end of the block.
# File lib/mocha/configuration.rb, line 95 def warn_when(action, &block) change_config action, :warn, &block end
@private
# File lib/mocha/configuration.rb, line 100 def warn_when?(action) configuration[action] == :warn end
Private Class Methods
@private
# File lib/mocha/configuration.rb, line 130 def change_config(action, new_value, &block) if block_given? temporarily_change_config action, new_value, &block else configuration[action] = new_value end end
@private
# File lib/mocha/configuration.rb, line 125 def configuration @configuration ||= DEFAULTS.dup end
@private
# File lib/mocha/configuration.rb, line 139 def temporarily_change_config(action, new_value) original_value = configuration[action] configuration[action] = new_value yield ensure configuration[action] = original_value end