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tests/wpt/web-platform-tests/docs/_writing-tests/testdriver.md

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+---
+layout: page
+title: testdriver.js Automation
+order: 8.5
+---
+
+testdriver.js provides a means to automate tests that cannot be
+written purely using web platform APIs.
+
+It is currently supported only for [testharness.js][testharness]
+tests.
+
+## API
+
+testdriver.js exposes its API through the `test_driver` variable in
+the global scope.
+
+NB: presently, testdriver.js only works in the top-level test browsing
+context (and not therefore in any frame or window opened from it).
+
+### `test_driver.click(element)`
+
+This function causes a click to occur on the target element (an
+`Element` object), potentially scrolling the document to make it
+possible to click it. It returns a `Promise` that resolves after the
+click has occured or rejects if the element cannot be clicked (for
+example, it is obscured by an element on top of it).
+
+Note that if the element to be clicked does not have a unique ID, the
+document must not have any DOM mutations made between the function
+being called and the promise settling.
+
+
+[testharness]: {{ site.baseurl }}{% link _writing-tests/testharness.md %}