Class: Mocha::Mock
- Inherits:
-
Object
- Object
- Mocha::Mock
- Defined in:
- lib/mocha/mock.rb
Overview
Traditional mock object.
All methods return an Expectation which can be further modified by methods on Expectation.
Stubs and expectations are basically the same thing. A stub is just an expectation of zero or more invocations. The #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. For example, an expects(:foo).once expectation only matches once and will be ignored on future invocations while an expects(:foo).at_least_once expectation will always be matched against invocations.
This scheme allows you to:
-
Set up default stubs in your the setup method of your test class and override some of those stubs in individual tests.
-
Set up different once expectations for the same method with different action per invocation. However, it's better to use the Expectation#returns method with multiple arguments to do this, as described below.
However, there are some possible "gotchas" caused by this scheme:
-
if you create an expectation and then a stub for the same method, the stub will always override the expectation and the expectation will never be met.
-
if you create a stub and then an expectation for the same method, the expectation will match, and when it stops matching the stub will be used instead, possibly masking test failures.
-
if you create different expectations for the same method, they will be invoked in the opposite order than that in which they were specified, rather than the same order.
The best thing to do is not set up multiple expectations and stubs for the same method with exactly the same matchers. Instead, use the Expectation#returns method with multiple arguments to create multiple actions for a method. You can also chain multiple calls to Expectation#returns and Expectation#raises (along with syntactic sugar Expectation#then if desired).
If you want to specify more complex ordering or order invocations across different mock objects, use the Expectation#in_sequence method to explicitly define a total or partial ordering of invocations.
Instance Method Summary (collapse)
-
- (Expectation) expects(method_name_or_hash, backtrace = nil)
(also: #__expects__)
Adds an expectation that the specified method must be called exactly once with any parameters.
-
- (Mock) responds_like(responder)
(also: #quacks_like)
Constrains the Mock instance so that it can only expect or stub methods to which responder responds.
-
- (Mock) responds_like_instance_of(responder_class)
(also: #quacks_like_instance_of)
Constrains the Mock instance so that it can only expect or stub methods to which an instance of the responder_class responds.
-
- (Expectation) stubs(method_name_or_hash, backtrace = nil)
(also: #__stubs__)
Adds an expectation that the specified method may be called any number of times with any parameters.
- - (Object) unstub(method_name)
Dynamic Method Handling
This class handles dynamic methods through the method_missing method
- (Object) method_missing(symbol, *arguments, &block)
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# File 'lib/mocha/mock.rb', line 287 def method_missing(symbol, *arguments, &block) if @responder and not @responder.respond_to?(symbol) raise NoMethodError, "undefined method `#{symbol}' for #{self.mocha_inspect} which responds like #{@responder.mocha_inspect}" end if matching_expectation_allowing_invocation = all_expectations.match_allowing_invocation(symbol, *arguments) matching_expectation_allowing_invocation.invoke(&block) else if (matching_expectation = all_expectations.match(symbol, *arguments)) || (!matching_expectation && !@everything_stubbed) if @unexpected_invocation.nil? @unexpected_invocation = UnexpectedInvocation.new(self, symbol, *arguments) matching_expectation.invoke(&block) if matching_expectation = @unexpected_invocation.full_description << @mockery.mocha_inspect else = @unexpected_invocation.short_description end raise ExpectationErrorFactory.build(, caller) end end end |
Instance Method Details
- (Expectation) expects(method_name) - (Expectation) expects(expected_methods_vs_return_values) Also known as: __expects__
Adds an expectation that the specified method must be called exactly once with any parameters.
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# File 'lib/mocha/mock.rb', line 105 def expects(method_name_or_hash, backtrace = nil) iterator = ArgumentIterator.new(method_name_or_hash) iterator.each { |*args| method_name = args.shift ensure_method_not_already_defined(method_name) expectation = Expectation.new(self, method_name, backtrace) expectation.returns(args.shift) if args.length > 0 @expectations.add(expectation) } end |
- (Mock) responds_like(responder) Also known as: quacks_like
Constrains the Mocha::Mock instance so that it can only expect or stub methods to which responder responds. The constraint is only applied at method invocation time.
A NoMethodError will be raised if the responder does not #respond_to? a method invocation (even if the method has been expected or stubbed).
The Mocha::Mock instance will delegate its #respond_to? method to the responder.
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# File 'lib/mocha/mock.rb', line 214 def responds_like(responder) @responder = responder self end |
- (Mock) responds_like_instance_of(responder_class) Also known as: quacks_like_instance_of
Constrains the Mocha::Mock instance so that it can only expect or stub methods to which an instance of the responder_class responds. The constraint is only applied at method invocation time. Note that the responder instance is instantiated using Class#allocate.
A NoMethodError will be raised if the responder instance does not #respond_to? a method invocation (even if the method has been expected or stubbed).
The Mocha::Mock instance will delegate its #respond_to? method to the responder instance.
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# File 'lib/mocha/mock.rb', line 245 def responds_like_instance_of(responder_class) responds_like(responder_class.allocate) end |
- (Expectation) stubs(method_name) - (Expectation) stubs(stubbed_methods_vs_return_values) Also known as: __stubs__
Adds an expectation that the specified method may be called any number of times with any parameters.
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# File 'lib/mocha/mock.rb', line 141 def stubs(method_name_or_hash, backtrace = nil) iterator = ArgumentIterator.new(method_name_or_hash) iterator.each { |*args| method_name = args.shift ensure_method_not_already_defined(method_name) expectation = Expectation.new(self, method_name, backtrace) expectation.at_least(0) expectation.returns(args.shift) if args.length > 0 @expectations.add(expectation) } end |