1 files changed, 73 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/promise/optimized-promise-already-resolved.js b/js/src/jit-test/tests/promise/optimized-promise-already-resolved.js
new file mode 100644
index 0000000000..69e7d95fe0
--- /dev/null
+++ b/js/src/jit-test/tests/promise/optimized-promise-already-resolved.js
@@ -0,0 +1,73 @@
+// Promise created with default resolution functions (without instances) should
+// behave in the same way as normal case.
+
+class MockPromise {
+  constructor(...args) {
+    return new Promise(...args);
+  }
+}
+
+for (const expected of ["resolve", "reject"]) {
+  for (const unexpected of ["resolve", "reject"]) {
+    let resolve, reject;
+    const p = new Promise((a, b) => {
+      resolve = a;
+      reject = b;
+    });
+
+    // To prevent fast path in Promise.resolve that returns the passed promise,
+    // modify constructor property.
+    p.constructor = MockPromise;
+
+    // Given `p` has custom constructor, Promise.resolve creates a new promise
+    // instead of returning `p` itself.
+    //
+    // Newly created promise `optimized` does not have resolution function
+    // instances.
+    const optimized = Promise.resolve(p);
+
+    // Newly created promise `normal` has resolution functions.
+    const normal = new Promise(r => r(p));
+
+    // These calls should be ignored because [[AlreadyResolved]] == true,
+    if (unexpected === "resolve") {
+      resolvePromise(optimized, "unexpected resolve optimized");
+      resolvePromise(normal, "unexpected resolve normal");
+    } else {
+      rejectPromise(optimized, "unexpected reject optimized");
+      rejectPromise(normal, "unexpected reject normal");
+    }
+
+    if (expected === "resolve") {
+      resolve("resolve");
+    } else {
+      reject("reject");
+    }
+
+    let optimized_resolutionValue, optimized_rejectionValue;
+    optimized.then(
+      x => { optimized_resolutionValue = x; },
+      x => { optimized_rejectionValue = x; }
+    );
+
+    let normal_resolutionValue, normal_rejectionValue;
+    normal.then(
+      x => { normal_resolutionValue = x; },
+      x => { normal_rejectionValue = x; }
+    );
+
+    drainJobQueue();
+
+    if (expected === "resolve") {
+      assertEq(optimized_resolutionValue, "resolve",
+               `${expected} + ${unexpected}`);
+      assertEq(normal_resolutionValue, "resolve",
+               `${expected} + ${unexpected}`);
+    } else {
+      assertEq(optimized_rejectionValue, "reject",
+               `${expected} + ${unexpected}`);
+      assertEq(normal_rejectionValue, "reject",
+               `${expected} + ${unexpected}`);
+    }
+  }
+}