2 files changed, 49 insertions, 0 deletions
diff --git a/dom/webshare/test/mochitest/mochitest.toml b/dom/webshare/test/mochitest/mochitest.toml
new file mode 100644
index 0000000000..5f7355a202
--- /dev/null
+++ b/dom/webshare/test/mochitest/mochitest.toml
@@ -0,0 +1,6 @@
+[DEFAULT]
+prefs = ["dom.webshare.enabled=true"]
+scheme = "https"
+skip-if = ["os == 'win'"] # https://bugzilla.mozilla.org/show_bug.cgi?id=1641280
+
+["test_navigator_share_consume_user_activation.html"]
diff --git a/dom/webshare/test/mochitest/test_navigator_share_consume_user_activation.html b/dom/webshare/test/mochitest/test_navigator_share_consume_user_activation.html
new file mode 100644
index 0000000000..9cb3f04d96
--- /dev/null
+++ b/dom/webshare/test/mochitest/test_navigator_share_consume_user_activation.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<title>Web Share: consume transient activation</title>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/EventUtils.js"></script>
+<link rel="stylesheet" href="/tests/SimpleTest/test.css" />
+<body>
+  <button id="share">Share</button>
+</body>
+<script>
+  // TODO: add a task that tests share() consume the transient user activation.
+  // Because OS-level prompt can't be cancelled, it's currently not possible to
+  // test this. We need to add a Web share Mocking service:
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1646229
+
+  // test that share() would be blocked with an already-consumed-activation.
+  add_task(async function blockedIfAlreadyConsumed() {
+    const wrappedDoc = SpecialPowers.wrap(document);
+    const button = document.getElementById("share");
+
+    // Kick off transient activation
+    synthesizeMouseAtCenter(button, {});
+
+    ok(
+      wrappedDoc.hasValidTransientUserGestureActivation,
+      "Activated by a gesture"
+    );
+
+    wrappedDoc.consumeTransientUserGestureActivation();
+
+    try {
+      const sharePromise = navigator.share({ title: "test" });
+      await sharePromise;
+      ok(false, "must throw because activation was already consumed");
+    } catch (err) {
+      is(err.name, "NotAllowedError", "Expected NotAllowedError DOMException");
+    } finally {
+      ok(
+        !wrappedDoc.hasValidTransientUserGestureActivation,
+        "share() must consume the activation"
+      );
+    }
+  });
+</script>