From dcc2312754fc3dfad686e5a2bd94bb4736ee0ef8 Mon Sep 17 00:00:00 2001
From: Gidi Meir Morris <github@gidi.io>
Date: Mon, 13 Jul 2020 19:38:52 +0100
Subject: [PATCH] added missing unit tests

---
 .../server/buffered_task_store.test.ts        | 82 +++++++++++++++++++
 .../server/buffered_task_store.ts             | 31 ++++---
 .../server/lib/bulk_operation_buffer.test.ts  | 22 +++--
 .../server/lib/bulk_operation_buffer.ts       | 35 ++++----
 .../task_manager/server/lib/result_type.ts    | 19 +++--
 .../task_manager/server/task_store.mock.ts    | 31 +++++++
 6 files changed, 179 insertions(+), 41 deletions(-)
 create mode 100644 x-pack/plugins/task_manager/server/buffered_task_store.test.ts
 create mode 100644 x-pack/plugins/task_manager/server/task_store.mock.ts

diff --git a/x-pack/plugins/task_manager/server/buffered_task_store.test.ts b/x-pack/plugins/task_manager/server/buffered_task_store.test.ts
new file mode 100644
index 0000000000000..1397d7ee6ee07
--- /dev/null
+++ b/x-pack/plugins/task_manager/server/buffered_task_store.test.ts
@@ -0,0 +1,82 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import uuid from 'uuid';
+import { taskStoreMock } from './task_store.mock';
+import { BufferedTaskStore } from './buffered_task_store';
+import { asErr, asOk } from './lib/result_type';
+import { TaskStatus } from './task';
+
+describe('Buffered Task Store', () => {
+  test('proxies the TaskStore for `maxAttempts` and `remove`', async () => {
+    const taskStore = taskStoreMock.create({ maxAttempts: 10 });
+    taskStore.bulkUpdate.mockResolvedValue([]);
+    const bufferedStore = new BufferedTaskStore(taskStore);
+
+    expect(bufferedStore.maxAttempts).toEqual(10);
+
+    bufferedStore.remove('1');
+    expect(taskStore.remove).toHaveBeenCalledWith('1');
+  });
+
+  describe('update', () => {
+    test("proxies the TaskStore's `bulkUpdate`", async () => {
+      const taskStore = taskStoreMock.create({ maxAttempts: 10 });
+      const bufferedStore = new BufferedTaskStore(taskStore);
+
+      const task = mockTask();
+
+      taskStore.bulkUpdate.mockResolvedValue([asOk(task)]);
+
+      expect(await bufferedStore.update(task)).toMatchObject(task);
+      expect(taskStore.bulkUpdate).toHaveBeenCalledWith([task]);
+    });
+
+    test('handles partially successfull bulkUpdates resolving each call appropriately', async () => {
+      const taskStore = taskStoreMock.create({ maxAttempts: 10 });
+      const bufferedStore = new BufferedTaskStore(taskStore);
+
+      const tasks = [mockTask(), mockTask(), mockTask()];
+
+      taskStore.bulkUpdate.mockResolvedValueOnce([
+        asOk(tasks[0]),
+        asErr(new Error('Oh no, something went terribly wrong')),
+        asOk(tasks[2]),
+      ]);
+
+      const results = [
+        bufferedStore.update(tasks[0]),
+        bufferedStore.update(tasks[1]),
+        bufferedStore.update(tasks[2]),
+      ];
+      expect(await results[0]).toMatchObject(tasks[0]);
+      expect(results[1]).rejects.toMatchInlineSnapshot(
+        `[Error: Oh no, something went terribly wrong]`
+      );
+      expect(await results[2]).toMatchObject(tasks[2]);
+    });
+  });
+});
+
+function mockTask() {
+  return {
+    id: `task_${uuid.v4()}`,
+    attempts: 0,
+    schedule: undefined,
+    params: { hello: 'world' },
+    retryAt: null,
+    runAt: new Date(),
+    scheduledAt: new Date(),
+    scope: undefined,
+    startedAt: null,
+    state: { foo: 'bar' },
+    status: TaskStatus.Idle,
+    taskType: 'report',
+    user: undefined,
+    version: '123',
+    ownerId: '123',
+  };
+}
diff --git a/x-pack/plugins/task_manager/server/buffered_task_store.ts b/x-pack/plugins/task_manager/server/buffered_task_store.ts
index 9836e8cda592b..4633b261ffed7 100644
--- a/x-pack/plugins/task_manager/server/buffered_task_store.ts
+++ b/x-pack/plugins/task_manager/server/buffered_task_store.ts
@@ -8,22 +8,27 @@ import { TaskStore } from './task_store';
 import { ConcreteTaskInstance } from './task';
 import { Updatable } from './task_runner';
 import { createBuffer, Operation } from './lib/bulk_operation_buffer';
-import { unwrapPromise, mapErr } from './lib/result_type';
+import { unwrapPromise, asErr, mapErr } from './lib/result_type';
 
 export class BufferedTaskStore implements Updatable {
-  private bufferedUpdate: Operation<ConcreteTaskInstance, Error>;
+  private bufferedUpdate: Operation<ConcreteTaskInstance, ConcreteTaskInstance, Error>;
   constructor(private readonly taskStore: TaskStore) {
-    this.bufferedUpdate = createBuffer<ConcreteTaskInstance, Error>(async (docs) => {
-      return (await taskStore.bulkUpdate(docs)).map((entityOrError, index) =>
-        mapErr(
-          (error: Error) => ({
-            entity: docs[index],
-            error,
-          }),
-          entityOrError
-        )
-      );
-    });
+    this.bufferedUpdate = createBuffer<ConcreteTaskInstance, ConcreteTaskInstance, Error>(
+      async (docs) => {
+        return (await taskStore.bulkUpdate(docs)).map((entityOrError, index) =>
+          mapErr(
+            (error: Error) =>
+              asErr({
+                // TaskStore's bulkUpdate maintains the order of the docs
+                // so we can rely on the index in the `docs` to match an entity with an index
+                entity: docs[index],
+                error,
+              }),
+            entityOrError
+          )
+        );
+      }
+    );
   }
 
   public get maxAttempts(): number {
diff --git a/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.test.ts b/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.test.ts
index 87e383b311a86..6e7ae97ea294e 100644
--- a/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.test.ts
+++ b/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.test.ts
@@ -33,10 +33,10 @@ function errorAttempts(task: TaskInstance): Err<OperationError<TaskInstance, Err
   });
 }
 
-describe('Task Store Buffer', () => {
+describe('Bulk Operation Buffer', () => {
   describe('createBuffer()', () => {
     test('batches up multiple Operation calls', async () => {
-      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, Error>> = jest.fn(
+      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, TaskInstance, Error>> = jest.fn(
         ([task1, task2]) => {
           return Promise.resolve([incrementAttempts(task1), incrementAttempts(task2)]);
         }
@@ -55,9 +55,11 @@ describe('Task Store Buffer', () => {
     });
 
     test('batch updates are executed at most by the next Event Loop tick', async () => {
-      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, Error>> = jest.fn((tasks) => {
-        return Promise.resolve(tasks.map(incrementAttempts));
-      });
+      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, TaskInstance, Error>> = jest.fn(
+        (tasks) => {
+          return Promise.resolve(tasks.map(incrementAttempts));
+        }
+      );
 
       const bufferedUpdate = createBuffer(bulkUpdate);
 
@@ -97,7 +99,7 @@ describe('Task Store Buffer', () => {
     });
 
     test('handles both resolutions and rejections at individual task level', async (done) => {
-      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, Error>> = jest.fn(
+      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, TaskInstance, Error>> = jest.fn(
         ([task1, task2, task3]) => {
           return Promise.resolve([
             incrementAttempts(task1),
@@ -129,9 +131,11 @@ describe('Task Store Buffer', () => {
     });
 
     test('handles bulkUpdate failure', async (done) => {
-      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, Error>> = jest.fn(() => {
-        return Promise.reject(new Error('bulkUpdate is an illusion'));
-      });
+      const bulkUpdate: jest.Mocked<BulkOperation<TaskInstance, TaskInstance, Error>> = jest.fn(
+        () => {
+          return Promise.reject(new Error('bulkUpdate is an illusion'));
+        }
+      );
 
       const bufferedUpdate = createBuffer(bulkUpdate);
 
diff --git a/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.ts b/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.ts
index a02a96607f4ec..3f5354e621555 100644
--- a/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.ts
+++ b/x-pack/plugins/task_manager/server/lib/bulk_operation_buffer.ts
@@ -13,24 +13,31 @@ export interface Entity {
   id: string;
 }
 
-export interface OperationError<H, E> {
-  entity: H;
-  error: E;
+export interface OperationError<Input, ErrorOutput> {
+  entity: Input;
+  error: ErrorOutput;
 }
 
-export type OperationResult<H, E> = Result<H, OperationError<H, E>>;
+export type OperationResult<Input, Output, ErrorOutput> = Result<
+  Output,
+  OperationError<Input, ErrorOutput>
+>;
 
-export type Operation<H, E> = (entity: H) => Promise<Result<H, E>>;
-export type BulkOperation<H, E> = (entities: H[]) => Promise<Array<OperationResult<H, E>>>;
+export type Operation<Input, Output, ErrorOutput> = (
+  entity: Input
+) => Promise<Result<Output, ErrorOutput>>;
+export type BulkOperation<Input, Output, ErrorOutput> = (
+  entities: Input[]
+) => Promise<Array<OperationResult<Input, Output, ErrorOutput>>>;
 
-export function createBuffer<H extends Entity, E>(
-  bulkOperation: BulkOperation<H, E>
-): Operation<H, E> {
+export function createBuffer<Input extends Entity, Output extends Entity, ErrorOutput>(
+  bulkOperation: BulkOperation<Input, Output, ErrorOutput>
+): Operation<Input, Output, ErrorOutput> {
   const flushBuffer = new Subject<void>();
   const storeUpdateBuffer = new Subject<{
-    entity: H;
-    onSuccess: (entity: Ok<H>) => void;
-    onFailure: (error: Err<E>) => void;
+    entity: Input;
+    onSuccess: (entity: Ok<Output>) => void;
+    onFailure: (error: Err<ErrorOutput>) => void;
   }>();
 
   storeUpdateBuffer
@@ -48,7 +55,7 @@ export function createBuffer<H extends Entity, E>(
               (entity) => {
                 entityById[entity.id].onSuccess(asOk(entity));
               },
-              ({ entity, error }: OperationError<H, E>) => {
+              ({ entity, error }: OperationError<Input, ErrorOutput>) => {
                 entityById[entity.id].onFailure(asErr(error));
               }
             )
@@ -59,7 +66,7 @@ export function createBuffer<H extends Entity, E>(
         });
     });
 
-  return async function (entity: H) {
+  return async function (entity: Input) {
     return new Promise((resolve, reject) => {
       // ensure we flush by the end of the "current" event loop tick
       setImmediate(() => flushBuffer.next());
diff --git a/x-pack/plugins/task_manager/server/lib/result_type.ts b/x-pack/plugins/task_manager/server/lib/result_type.ts
index a7fbdf80679d7..b0eee7a10fc56 100644
--- a/x-pack/plugins/task_manager/server/lib/result_type.ts
+++ b/x-pack/plugins/task_manager/server/lib/result_type.ts
@@ -31,25 +31,34 @@ export function asErr<T>(error: T): Err<T> {
   };
 }
 
+export function isResult<T, E>(maybeResult: unknown): maybeResult is Result<T, E> {
+  return (
+    (maybeResult as Result<T, E>)?.tag === 'ok' || (maybeResult as Result<T, E>)?.tag === 'err'
+  );
+}
+
 export function isOk<T, E>(result: Result<T, E>): result is Ok<T> {
-  return result.tag === 'ok';
+  return result?.tag === 'ok';
 }
 
 export function isErr<T, E>(result: Result<T, E>): result is Err<E> {
   return !isOk(result);
 }
 
-export async function promiseResult<T, E>(future: Promise<T>): Promise<Result<T, E>> {
+export async function promiseResult<T, E>(
+  future: Promise<T | Result<T, E>>
+): Promise<Result<T, E>> {
   try {
-    return asOk(await future);
+    const result = await future;
+    return isResult(result) ? result : asOk(result);
   } catch (e) {
-    return asErr(e);
+    return isResult<T, E>(e) ? e : asErr(e);
   }
 }
 
 export async function unwrapPromise<T, E>(future: Promise<Result<T, E>>): Promise<T> {
   return map(
-    await future,
+    await promiseResult(future),
     (value: T) => Promise.resolve(value),
     (err: E) => Promise.reject(err)
   );
diff --git a/x-pack/plugins/task_manager/server/task_store.mock.ts b/x-pack/plugins/task_manager/server/task_store.mock.ts
new file mode 100644
index 0000000000000..86db695bc5e2c
--- /dev/null
+++ b/x-pack/plugins/task_manager/server/task_store.mock.ts
@@ -0,0 +1,31 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { TaskStore } from './task_store';
+
+interface TaskStoreOptions {
+  maxAttempts?: number;
+  index?: string;
+  taskManagerId?: string;
+}
+export const taskStoreMock = {
+  create({ maxAttempts = 0, index = '', taskManagerId = '' }: TaskStoreOptions) {
+    const mocked = ({
+      update: jest.fn(),
+      remove: jest.fn(),
+      schedule: jest.fn(),
+      claimAvailableTasks: jest.fn(),
+      bulkUpdate: jest.fn(),
+      get: jest.fn(),
+      getLifecycle: jest.fn(),
+      fetch: jest.fn(),
+      maxAttempts,
+      index,
+      taskManagerId,
+    } as unknown) as jest.Mocked<TaskStore>;
+    return mocked;
+  },
+};