[Solved] How can you test that a method in a service calls a dependency's method using spies in Angular? — Ans: Inject the dependency, spy on its method, then verify spy was called | Angular

Angular - Testing

How can you test that a method in a service calls a dependency's method using spies in Angular?

AUse TestBed.resetTestingModule before each test

BReplace the dependency with a new instance without spying

CCall the service method without injecting dependencies

DInject the dependency, spy on its method, then verify spy was called

Step-by-Step Solution

Solution:

Step 1: Inject dependency to spy on
Get the dependency instance via TestBed.inject to spy on its methods.
Step 2: Create spy and verify call
Use spyOn to watch the method, call service method, then check spy call.
Final Answer:
Inject the dependency, spy on its method, then verify spy was called -> Option D
Quick Check:
Spy usage for dependency call = D [OK]

Quick Trick: Spy on injected dependency methods to verify calls [OK]

Common Mistakes:

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How can you test that a method in a service calls a dependency's method using spies in Angular?