Angular - Testing
You want to test a component that calls a service method returning an Observable. How do you mock the service method to emit a value 'test' synchronously?
You want to test a component that calls a service method returning an Observable. How do you mock the service method to emit a value 'test' synchronously?
hard📝 Application Q8 of 15
Step-by-Step Solution
Solution:
Step 1: Identify Observable return type
The service method returns an Observable, so the mock must return an Observable too.Step 2: Use jasmine spy with returnValue
Use jasmine.createSpyObj to create a spy method and returnof('test')to emit synchronously.Final Answer:
Use jasmine.createSpyObj and returnValue(of('test')) for the method -> Option CQuick Check:
Mock Observable with of() in spy [OK]
Quick Trick: Mock Observable methods with of() in jasmine spies [OK]
Common Mistakes:
- Returning Promise instead of Observable
- Returning raw string instead of Observable
- Using HttpClientTestingModule for non-HTTP mocks
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