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Generate event object for fireEvent #1171

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192 changes: 147 additions & 45 deletions src/__tests__/fireEvent.test.tsx
Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,28 @@ const CustomEventComponentWithCustomName = ({
);

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)

const handlerMock = jest.fn();

const { getByText } = render(
<View>
<CustomEventComponent onCustomEvent={handlerMock} />
</View>
);

fireEvent(
getByText('Custom event component'),
'customEvent',
'some_argument_1',
'some_argument_2'
);

expect(handlerMock).toHaveBeenCalledWith(
'some_argument_1',
'some_argument_2'
);
});

test('should invoke specified event', () => {
const onPressMock = jest.fn();
const { getByText } = render(
Expand All @@ -67,6 +89,37 @@ describe('fireEvent', () => {
expect(onPressMock).toHaveBeenCalled();
});

test('should pass along provided event data', () => {
const onPressMock = jest.fn();
const text = 'Fireevent press';
const eventData = {
nativeEvent: {
pageX: 20,
pageY: 30,
},
};
const { getByText } = render(
<OnPressComponent onPress={onPressMock} text={text} />
);

fireEvent(getByText(text), 'press', eventData);

expect(onPressMock).toHaveBeenCalledWith(eventData);
});

test('should not pass a generated event object by default with the string syntax', () => {
const onPressMock = jest.fn();
const text = 'Fireevent press';
const { getByText } = render(
<OnPressComponent onPress={onPressMock} text={text} />
);

fireEvent(getByText(text), 'press');

expect(onPressMock).toHaveBeenCalled();
expect(onPressMock).not.toHaveBeenCalledWith({ eventName: 'press' });
});

test('should invoke specified event on parent element', () => {
const onPressMock = jest.fn();
const text = 'New press text';
Expand Down Expand Up @@ -104,64 +157,113 @@ describe('fireEvent', () => {
});
});

test('fireEvent.press', () => {
const onPressMock = jest.fn();
const text = 'Fireevent press';
const eventData = {
nativeEvent: {
pageX: 20,
pageY: 30,
},
};
const { getByText } = render(
<OnPressComponent onPress={onPressMock} text={text} />
);
describe('fireEvent.press', () => {
test('should pass along provided event data', () => {
const onPressMock = jest.fn();
const text = 'Fireevent press';
const eventData = {
nativeEvent: {
pageX: 20,
pageY: 30,
},
};
const { getByText } = render(
<OnPressComponent onPress={onPressMock} text={text} />
);

fireEvent.press(getByText(text), eventData);
fireEvent.press(getByText(text), eventData);

expect(onPressMock).toHaveBeenCalledWith(eventData);
});

expect(onPressMock).toHaveBeenCalledWith(eventData);
test('should pass a generated event object by default with the function syntax', () => {
const onPressMock = jest.fn();
const text = 'Fireevent press';
const { getByText } = render(
<OnPressComponent onPress={onPressMock} text={text} />
);

fireEvent.press(getByText(text));

expect(onPressMock).toHaveBeenCalledWith({ eventName: 'press' });
});
});

test('fireEvent.scroll', () => {
const onScrollMock = jest.fn();
const eventData = {
nativeEvent: {
contentOffset: {
y: 200,
describe('fireEvent.scroll', () => {
test('should pass along provided event data', () => {
const onScrollMock = jest.fn();
const eventData = {
nativeEvent: {
contentOffset: {
y: 200,
},
},
},
};
};

const { getByText } = render(
<ScrollView onScroll={onScrollMock}>
<Text>XD</Text>
</ScrollView>
);
const { getByText } = render(
<ScrollView onScroll={onScrollMock}>
<Text>XD</Text>
</ScrollView>
);

fireEvent.scroll(getByText('XD'), eventData);

expect(onScrollMock).toHaveBeenCalledWith(eventData);
});
test('should pass a generated event object by default', () => {
const onScrollMock = jest.fn();
const eventData = { eventName: 'scroll' };

const { getByText } = render(
<ScrollView onScroll={onScrollMock}>
<Text>XD</Text>
</ScrollView>
);

fireEvent.scroll(getByText('XD'), eventData);
fireEvent.scroll(getByText('XD'));

expect(onScrollMock).toHaveBeenCalledWith(eventData);
expect(onScrollMock).toHaveBeenCalledWith(eventData);
});
});

test('fireEvent.changeText', () => {
const onChangeTextMock = jest.fn();
const CHANGE_TEXT = 'content';
describe('fireEvent.changeText', () => {
test('should pass the provided text', () => {
const onChangeTextMock = jest.fn();
const CHANGE_TEXT = 'content';

const { getByPlaceholderText } = render(
<View>
<TextInput
placeholder="Customer placeholder"
onChangeText={onChangeTextMock}
/>
</View>
);
const { getByPlaceholderText } = render(
<View>
<TextInput
placeholder="Customer placeholder"
onChangeText={onChangeTextMock}
/>
</View>
);

fireEvent.changeText(
getByPlaceholderText('Customer placeholder'),
CHANGE_TEXT
);
fireEvent.changeText(
getByPlaceholderText('Customer placeholder'),
CHANGE_TEXT
);

expect(onChangeTextMock).toHaveBeenCalledWith(CHANGE_TEXT);
});

test('what if no text is provided', () => {
const onChangeTextMock = jest.fn();

const { getByPlaceholderText } = render(
<View>
<TextInput
placeholder="Customer placeholder"
onChangeText={onChangeTextMock}
/>
</View>
);

expect(onChangeTextMock).toHaveBeenCalledWith(CHANGE_TEXT);
fireEvent.changeText(getByPlaceholderText('Customer placeholder'));

expect(onChangeTextMock).toHaveBeenCalledWith();
});
});

test('custom component with custom event name', () => {
Expand Down
49 changes: 34 additions & 15 deletions src/fireEvent.ts
Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,7 @@ const invokeEvent = (
element: ReactTestInstance,
eventName: string,
callsite?: any,
...data: Array<any>
...callBackValues: Array<any>
) => {
const handler = findEventHandler(element, eventName, callsite);

Expand All @@ -118,7 +118,7 @@ const invokeEvent = (
let returnValue;

act(() => {
returnValue = handler(...data);
returnValue = handler(...callBackValues);
});

return returnValue;
Expand All @@ -127,23 +127,42 @@ const invokeEvent = (
const toEventHandlerName = (eventName: string) =>
`on${eventName.charAt(0).toUpperCase()}${eventName.slice(1)}`;

const pressHandler = (element: ReactTestInstance, ...data: Array<any>): void =>
invokeEvent(element, 'press', pressHandler, ...data);
const changeTextHandler = (
element: ReactTestInstance,
...data: Array<any>
): void => invokeEvent(element, 'changeText', changeTextHandler, ...data);
const scrollHandler = (element: ReactTestInstance, ...data: Array<any>): void =>
invokeEvent(element, 'scroll', scrollHandler, ...data);
): void => {
invokeEvent(element, 'changeText', changeTextHandler, ...data);
};

const fireEvent = (
element: ReactTestInstance,
eventName: string,
...data: Array<any>
): void => invokeEvent(element, eventName, fireEvent, ...data);
const generatedEventObject = (eventName: string) => {
// This should use the (as-yet nonexistent) event map to return a "real" object, just like
// https://github.com/testing-library/dom-testing-library/blob/29a17cb5f14b0f30f08a29172e35e55c3e8ba529/src/event-map.js#L0-L1
return { eventName: eventName };
};

const addHandler = (eventName: string) => {
return (element: ReactTestInstance, ...data: Array<any>): void => {
const callBackValue =
data.length > 0 ? data : [generatedEventObject(eventName)];
invokeEvent(element, eventName, addHandler, ...callBackValue);
};
};

type FireEvent = {
(element: ReactTestInstance, eventName: string, ...data: Array<any>): void;
[key: string]: (element: ReactTestInstance, ...data: Array<any>) => void;
};

const fireEvent = <FireEvent>(
((element: ReactTestInstance, eventName: string, ...data: Array<any>) =>
invokeEvent(element, eventName, fireEvent, ...data))
);

fireEvent['changeText'] = changeTextHandler;

fireEvent.press = pressHandler;
fireEvent.changeText = changeTextHandler;
fireEvent.scroll = scrollHandler;
// map.keys.forEach ...
['press', 'scroll'].forEach((eventName: string) => {
fireEvent[eventName] = addHandler(eventName);
});

export default fireEvent;