LibJS: Implement Promise.all on the Promise constructor

1 files changed, 116 insertions, 0 deletions

diff --git a/Userland/Libraries/LibJS/Tests/builtins/Promise/Promise.all.js b/Userland/Libraries/LibJS/Tests/builtins/Promise/Promise.all.js
new file mode 100644
index 0000000000..ff18a8dbfa
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/builtins/Promise/Promise.all.js
@@ -0,0 +1,116 @@
+test("length is 1", () => {
+    expect(Promise.all).toHaveLength(1);
+});
+
+describe("normal behavior", () => {
+    test("returns a Promise", () => {
+        const promise = Promise.all();
+        expect(promise).toBeInstanceOf(Promise);
+    });
+
+    test("resolve", () => {
+        const promise1 = Promise.resolve(3);
+        const promise2 = 42;
+        const promise3 = new Promise((resolve, reject) => {
+            resolve("foo");
+        });
+
+        let resolvedValues = null;
+        let wasRejected = false;
+
+        Promise.all([promise1, promise2, promise3]).then(
+            values => {
+                resolvedValues = values;
+            },
+            () => {
+                wasRejected = true;
+            }
+        );
+
+        runQueuedPromiseJobs();
+        expect(resolvedValues).toEqual([3, 42, "foo"]);
+        expect(wasRejected).toBeFalse();
+    });
+
+    test("reject", () => {
+        const promise1 = Promise.resolve(3);
+        const promise2 = 42;
+        const promise3 = new Promise((resolve, reject) => {
+            reject("foo");
+        });
+
+        let rejectionReason = null;
+        let wasResolved = false;
+
+        Promise.all([promise1, promise2, promise3]).then(
+            () => {
+                wasResolved = true;
+            },
+            reason => {
+                rejectionReason = reason;
+            }
+        );
+
+        runQueuedPromiseJobs();
+        expect(rejectionReason).toBe("foo");
+        expect(wasResolved).toBeFalse();
+    });
+});
+
+describe("exceptional behavior", () => {
+    test("cannot invoke capabilities executor twice", () => {
+        function fn() {}
+
+        expect(() => {
+            function promise(executor) {
+                executor(fn, fn);
+                executor(fn, fn);
+            }
+
+            Promise.all.call(promise, []);
+        }).toThrow(TypeError);
+
+        expect(() => {
+            function promise(executor) {
+                executor(fn, undefined);
+                executor(fn, fn);
+            }
+
+            Promise.all.call(promise, []);
+        }).toThrow(TypeError);
+
+        expect(() => {
+            function promise(executor) {
+                executor(undefined, fn);
+                executor(fn, fn);
+            }
+
+            Promise.all.call(promise, []);
+        }).toThrow(TypeError);
+    });
+
+    test("promise without resolve method", () => {
+        expect(() => {
+            function promise(executor) {}
+            Promise.all.call(promise, []);
+        }).toThrow(TypeError);
+    });
+
+    test("no parameters", () => {
+        let rejectionReason = null;
+        Promise.all().catch(reason => {
+            rejectionReason = reason;
+        });
+        runQueuedPromiseJobs();
+        expect(rejectionReason).toBeInstanceOf(TypeError);
+    });
+
+    test("non-iterable", () => {
+        let rejectionReason = null;
+        Promise.all(1).catch(reason => {
+            rejectionReason = reason;
+        });
+        runQueuedPromiseJobs();
+        expect(rejectionReason).toBeInstanceOf(TypeError);
+    });
+});