How does Sinon stub work?
Sinon is a stubbing library, not a module interception library. To stub a dependency (imported module) of a module under test you have to import it explicitly in your test and stub the desired method. For the stubbing to work, the stubbed method cannot be destructured, neither in the module under test nor in the test.
What is stub Sinon?
Test stubs are functions (spies) with pre-programmed behavior. They support the full test spy API in addition to methods which can be used to alter the stub’s behavior. As spies, stubs can be either anonymous, or wrap existing functions.
How do you clear a Sinon stub?
All you have to do is create a sandbox in the very first describe block so that, it is accessible throughout all the test cases. And once you are done with all the test cases you should release the original methods and clean up the stubs using the method sandbox.
How do you use a stub?
You use stubs when you just want a function to return some value (or do nothing). You don’t really care if the function was called or not, you just want to isolate things. Mocks are more powerful, as you can also keep track if the function was called, how many times, and even do things with values your function gets.
What is Sinon Spy ()?
The function sinon. spy returns a Spy object, which can be called like a function, but also contains properties with information on any calls made to it. In the example above, the firstCall property has information about the first call, such as firstCall. args which is the list of arguments passed.
What is the purpose of writing stub routines?
These are often used as placeholders, so that overall program structure can be worked out first, and then the details.
Why do we need stub?
Stubs are used during Top-down integration testing, in order to simulate the behaviour of the lower-level modules that are not yet integrated. Stubs are the modules that act as temporary replacement for a called module and give the same output as that of the actual product.
When do you use a stub in Sinon?
Use stubs when you want to control the method behaviour, for instance force a method to throwing an exception to check the error handling functionalities. prevent a method to get call directly to stop triggering undesired behaviour (sinon stub documentaion).
When to call the original method in a stub?
Causes the original method wrapped into the stub to be called when none of the conditional stubs are matched. Causes the original method wrapped into the stub to be called using the new operator when none of the conditional stubs are matched. Like stub.callsArg (index); but with an additional parameter to pass the this context.
How are stubs used in xUnit test pattern?
“stubs replace the real object with a test specific object that feed the desire indirect inputs into the system under test”. (xUnit test pattern) stubs function has pre-programmed behaviour. they support all the spies functionalities as well. When to use Stub?
When to use usingpromise method in Sinon?
When constructing the Promise, sinon uses the Promise.resolve method. You are responsible for providing a polyfill in environments which do not provide Promise. The Promise library can be overwritten using the usingPromise method. Since [email protected]