| fixture |
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fixtures/before-screenshot.js |
In some cases, it can be necessary to perform actions on a fixture prior to taking a screenshot. For example, you might want to test a part of a fixture that is only visible after clicking a button.
You can execute a custom function after the content is generated by
your fixture, but before the screenshot, by supplying a beforeScreenshot function
in your fixture.
The function will be executed in the browser's page context. The browser's
execution context is available within the function. For example, you can access the document via
window.document.
As the function is in the browser context, you can't access local variables from the fixture enclosure directly,
but you can pass additional arguments using the beforeScreenshotArgs field. See an example in before-screenshot-with-args.md.
For asynchronous functions, return a Promise. Appraise will wait until the promise resolves before
taking the screenshot.
This page is an executable example of delayed screenshot execution, using the before-screenshot.js.
This fixture generates some HTML that initially has a hidden element
text: I am hiddenAfter clicking the button, a previously hidden text appears:
