Create test helpers to test a step in isolation

[sergiofilhowz]

The developers want to be able to test a single step in isolation and be able to:

• Check emitted events
• Check state changes
• Check stream changes

Emitted events should not trigger other steps, they're mostly for test assessment.

Example

const handler = (input, { emit }) => {
  if (input.name === 'test') {
     await emit({ topic: 'another-topic', data: { name: input.name });
  }
}

I want to test this step and check if input { name: 'fail' } will trigger an emit and if input { name: 'test' } will trigger an event.

What I expect in this helper functions is a way to create FlowContext.

const mockedContext = tester.createMockedContext()
// ...
mockedContext.emit.toHaveBeenCalledWith({/* ... */}) 

Create examples where we could use to test only event steps directly

Acceptance Criteria

• [ ] Code must be clean
• [ ] Code for test should be simple to understand
• [ ] Test utility should be able to create a FlowContext to mock and validate Streams, State and Emits
• [ ] New documentation section explaining how to test a step in isolation

[Tanmay-008]

Is anyone working on this or can I start it?

[riturajFi]

This is cool! I am on it