1 files changed, 73 insertions, 0 deletions
diff --git a/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs b/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs
new file mode 100644
index 0000000000..0a8a0439e1
--- /dev/null
+++ b/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs
@@ -0,0 +1,73 @@
+// Usage note: if you use these more than once in a given file, be sure to
+// clean up any navigate event listeners, e.g. by using { once: true }, between
+// tests.
+
+const TAB_KEY = "\uE004";
+
+export function testFocusWasReset(setupFunc, description) {
+  promise_test(async t => {
+    setupFunc(t);
+
+    const button = document.body.appendChild(document.createElement("button"));
+    const button2 = document.body.appendChild(document.createElement("button"));
+    button2.tabIndex = 0;
+    t.add_cleanup(() => {
+      button.remove();
+      button2.remove();
+    });
+
+    assert_equals(document.activeElement, document.body, "Start on body");
+    button.focus();
+    assert_equals(document.activeElement, button, "focus() worked");
+
+    const { committed, finished } = navigation.navigate("#" + location.hash.substring(1) + "1");
+
+    await committed;
+    assert_equals(document.activeElement, button, "Focus stays on the button during the transition");
+
+    await finished.catch(() => {});
+    assert_equals(document.activeElement, document.body, "Focus reset after the transition");
+
+    button2.onfocus = t.unreached_func("button2 must not be focused after pressing Tab");
+    const focusPromise = waitForFocus(t, button);
+    await test_driver.send_keys(document.body, TAB_KEY);
+    await focusPromise;
+  }, description);
+}
+
+export function testFocusWasNotReset(setupFunc, description) {
+  promise_test(async t => {
+    setupFunc(t);
+
+    const button = document.body.appendChild(document.createElement("button"));
+    const button2 = document.body.appendChild(document.createElement("button"));
+    button2.tabIndex = 0;
+    t.add_cleanup(() => {
+      button.remove();
+      button2.remove();
+    });
+
+    assert_equals(document.activeElement, document.body, "Start on body");
+    button.focus();
+    assert_equals(document.activeElement, button, "focus() worked");
+
+    const { committed, finished } = navigation.navigate("#" + location.hash.substring(1) + "1");
+
+    await committed;
+    assert_equals(document.activeElement, button, "Focus stays on the button during the transition");
+
+    await finished.catch(() => {});
+    assert_equals(document.activeElement, button, "Focus stays on the button after the transition");
+
+    button.onfocus = t.unreached_func("button must not be focused after pressing Tab");
+    const focusPromise = waitForFocus(t, button2);
+    await test_driver.send_keys(document.body, TAB_KEY);
+    await focusPromise;
+  }, description);
+}
+
+function waitForFocus(t, target) {
+  return new Promise(resolve => {
+    target.addEventListener("focus", () => resolve(), { once: true });
+  });
+}