1 files changed, 38 insertions, 0 deletions
diff --git a/testing/web-platform/tests/web-locks/mode-shared.tentative.https.any.js b/testing/web-platform/tests/web-locks/mode-shared.tentative.https.any.js
new file mode 100644
index 0000000000..fc4a6012fa
--- /dev/null
+++ b/testing/web-platform/tests/web-locks/mode-shared.tentative.https.any.js
@@ -0,0 +1,38 @@
+// META: title=Web Locks API: Shared Mode
+// META: global=window,dedicatedworker,sharedworker,serviceworker
+
+'use strict';
+
+promise_test(async t => {
+  const granted = [];
+  function log_grant(n) { return () => { granted.push(n); }; }
+
+  await Promise.all([
+    navigator.locks.request('a', {mode: 'shared'}, log_grant(1)),
+    navigator.locks.request('b', {mode: 'shared'}, log_grant(2)),
+    navigator.locks.request('c', {mode: 'shared'}, log_grant(3)),
+    navigator.locks.request('a', {mode: 'shared'}, log_grant(4)),
+    navigator.locks.request('b', {mode: 'shared'}, log_grant(5)),
+    navigator.locks.request('c', {mode: 'shared'}, log_grant(6)),
+  ]);
+
+  assert_array_equals(granted, [1, 2, 3, 4, 5, 6]);
+}, 'Lock requests are granted in order');
+
+promise_test(async t => {
+  let a_acquired = false, a_acquired_again = false;
+
+  await navigator.locks.request('a', {mode: 'shared'}, async lock => {
+    a_acquired = true;
+
+    // Since lock is held, this request would be blocked if the
+    // lock was not 'shared', causing this test to time out.
+
+    await navigator.locks.request('a', {mode: 'shared'}, lock => {
+      a_acquired_again = true;
+    });
+  });
+
+  assert_true(a_acquired, 'first lock acquired');
+  assert_true(a_acquired_again, 'second lock acquired');
+}, 'Shared locks are not exclusive');