Generate event object for fireEvent - #1171
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| describe('fireEvent', () => { | ||
| test('QUESTION: is there a kind of event that takes multiple arguments?', () => { |
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AFAIK events by convention take a single argument of Event type or subtype. We also have onChangeText which gets a single string value, but that seems to be simplified version of onChange. I would assume that we can focus only on handling single argument. That should simplify the typing, while we can always refactor if there would be any such event.
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Thanks for this info! BTW I noticed that I didn't clearly link to our additional questions from here. Here they are: #714 (comment)
mdjastrzebski
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mdjastrzebski
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So far, so good! I think it would be wise to start by researching real RN app behaviour and coding that into unit tests.
| const generatedEventObject = { someKey: 'value' }; | ||
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| let defaultCallbackValues = | ||
| eventName === 'changeText' ? [] : [generatedEventObject]; | ||
| const handlerCallbackValues = data.length > 0 ? data : defaultCallbackValues; | ||
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| let returnValue; | ||
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| act(() => { | ||
| returnValue = handler(...data); | ||
| returnValue = handler(...handlerCallbackValues); | ||
| }); |
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Generally we would like to follow DTL's fireEvent implementation, with adjustments necessary to account for differences between RN and React DOM.
- They have event map record which holds mapping from event name to event object constructor name and some default init props: https://github.com/testing-library/dom-testing-library/blob/main/src/event-map.js
- They only apply default event iff someone uses
fireEvent.xxx. They do not seem to apply in when usingfireEvent('xxx'):
- https://github.com/testing-library/dom-testing-library/blob/edffb7c5ec2e4afd7f6bedf842c669ddbfb73297/src/events.js#L5
- https://github.com/testing-library/dom-testing-library/blob/edffb7c5ec2e4afd7f6bedf842c669ddbfb73297/src/events.js#L99
- Important parts seems to be dispatching that event in context of given node. See: https://github.com/testing-library/dom-testing-library/blob/edffb7c5ec2e4afd7f6bedf842c669ddbfb73297/src/events.js#L17
In DTL they have element.displatchEvent, but in ourcase it seems that we have to manually assign target property of event, since our ReactTestInstance does not implement EventTarget which achieves that effect automatically for RTL.
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Superseded by #1258 |
2 participants
HT to @jlcampbell and @MLee21 for collaborating with me on this investigation and PR!
Summary
This PR shows initial work toward implementing #714. It is not yet ready to merge: additional questions are posted in the issue.
Test plan
Run
fireEvent.tsand note that the tests pass.