Add support for switch to toBeChecked matcher

[sladek-jan]

Describe the Feature

• it would be possible to use the toBeChecked matcher for elements with the switch role

Possible Implementations

• add 'switch' to the condition here: https://github.com/callstack/react-native-testing-library/blob/899de72aaf3c5e81363afd066c62e41fb64e2d2d/src/matchers/to-be-checked.tsx#L41

Related Issues

https://github.com/callstack/react-native-testing-library/issues/1457

[mdjastrzebski]

I will have to consider what is the best value to solve the Switch checking problem.

The Switch component in React Native codebase does not actually rely on the checked state. See: https://github.com/facebook/react-native/blob/3350050edc6bdec1652448863ab0c6872d2ac4ed/packages/react-native/Libraries/Components/Switch/Switch.js#L188

It uses value for that, and setting this prop does to affect the accessibilityState prop:

        <RCTSwitch
          accessibilityRole="switch"
          onChange={[Function handleChange]}
          onResponderTerminationRequest={[Function returnsFalse]}
          onStartShouldSetResponder={[Function returnsTrue]}
          style={
            {
              "height": 31,
              "width": 51,
            }
          }
          testID="switch"
          value={true}
        />,

This is different then web, where switch role is related to the checked prop: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/switch_role

Perhaps this should (also) be handled at the RN repo level.

[mdjastrzebski]

Yeah, you have a point there. Let's fix it. 🔨 The implementation is slightly more complex tough.

[sladek-jan]

Ok, thank you! For now, I solved it using this snippet as a workaround:

const expectSwitchToBeChecked = (instance: ReactTestInstance, checked: boolean) => {
    expect(instance.props.accessibilityState.checked).toBe(checked);
};

[mdjastrzebski]

@sladek-jan from my research, for native Switch element you should examine element.props.value instead of accessibilityState which afaik is not set by the Switch control itself.

[mdjastrzebski]

@sladek-jan Just for clarity which switch component are you using? Switch from React Native package or something else?

[sladek-jan]

Ah, sorry for the confusion, we are using a design library in the project and under the hood, it renders a custom View with the role 'switch', which is controlled by setting the 'aria-checked' prop. So my workaround probably doesn't apply to the real RN Switch.

[mdjastrzebski]

nvm, let's ship both Switch element and switch role 🤣