1 files changed, 122 insertions, 0 deletions
diff --git a/polygerrit-ui/app/services/scheduler/retry-scheduler_test.ts b/polygerrit-ui/app/services/scheduler/retry-scheduler_test.ts
new file mode 100644
index 0000000000..988b167071
--- /dev/null
+++ b/polygerrit-ui/app/services/scheduler/retry-scheduler_test.ts
@@ -0,0 +1,122 @@
+/**
+ * @license
+ * Copyright 2022 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import '../../test/common-test-setup-karma.js';
+import {assertFails} from '../../test/test-utils.js';
+import {Scheduler} from './scheduler';
+import {RetryScheduler, RetryError} from './retry-scheduler';
+import {FakeScheduler} from './fake-scheduler';
+import {SinonFakeTimers} from 'sinon';
+
+suite('retry scheduler', () => {
+  let clock: SinonFakeTimers;
+  let fakeScheduler: FakeScheduler<number>;
+  let scheduler: Scheduler<number>;
+  setup(() => {
+    clock = sinon.useFakeTimers();
+    fakeScheduler = new FakeScheduler<number>();
+    scheduler = new RetryScheduler<number>(fakeScheduler, 3, 50, 1);
+  });
+
+  async function waitForRetry(ms: number) {
+    // Flush the promise so that we can reach untilTimeout
+    await flush();
+    // Advance the clock.
+    clock.tick(ms);
+    // Flush the promise that waits for the clock.
+    await flush();
+  }
+
+  test('executes tasks', async () => {
+    const promise = scheduler.schedule(async () => 1);
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    fakeScheduler.resolve();
+    assert.equal(fakeScheduler.scheduled.length, 0);
+    const val = await promise;
+    assert.equal(val, 1);
+  });
+
+  test('propagates task errors', async () => {
+    const error = new Error('This is an error');
+    const promise = scheduler.schedule(async () => {
+      throw error;
+    });
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    assertFails(promise, error);
+    fakeScheduler.resolve();
+    assert.equal(fakeScheduler.scheduled.length, 0);
+    await promise.catch((reason: Error) => {
+      assert.equal(reason, error);
+    });
+  });
+
+  test('propagates subscheduler errors', async () => {
+    const error = new Error('This is an error');
+    const promise = scheduler.schedule(async () => 1);
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    assertFails(promise, error);
+    fakeScheduler.reject(error);
+    assert.equal(fakeScheduler.scheduled.length, 0);
+    await promise.catch((reason: Error) => {
+      assert.equal(reason, error);
+    });
+  });
+
+  test('retries on retryable error', async () => {
+    let retries = 1;
+    const promise = scheduler.schedule(async () => {
+      if (retries-- > 0) throw new RetryError('Retrying');
+      return 1;
+    });
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    fakeScheduler.resolve();
+    assert.equal(fakeScheduler.scheduled.length, 0);
+    await waitForRetry(50);
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    fakeScheduler.resolve();
+    const val = await promise;
+    assert.equal(val, 1);
+  });
+
+  test('retries up to 3 times', async () => {
+    let retries = 3;
+    const promise = scheduler.schedule(async () => {
+      if (retries-- > 0) throw new RetryError('Retrying');
+      return 1;
+    });
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    for (let i = 0; i < 3; i++) {
+      fakeScheduler.resolve();
+      assert.equal(fakeScheduler.scheduled.length, 0);
+      await waitForRetry(50);
+      assert.equal(fakeScheduler.scheduled.length, 1);
+    }
+    fakeScheduler.resolve();
+    const val = await promise;
+    assert.equal(val, 1);
+  });
+
+  test('fails after more than 3 times', async () => {
+    let retries = 4;
+    const promise = scheduler.schedule(async () => {
+      if (retries-- > 0) throw new RetryError(retries, `Retrying ${retries}`);
+      return 1;
+    });
+    assert.equal(fakeScheduler.scheduled.length, 1);
+    for (let i = 0; i < 3; i++) {
+      fakeScheduler.resolve();
+      assert.equal(fakeScheduler.scheduled.length, 0);
+      await waitForRetry(50);
+      assert.equal(fakeScheduler.scheduled.length, 1);
+    }
+    fakeScheduler.resolve();
+    assertFails(promise);
+    // The error we get back should be the last error.
+    await promise.catch((reason: RetryError<number>) => {
+      assert.equal(reason.payload, 0);
+      assert.equal(reason.message, 'Retrying 0');
+    });
+  });
+});