test(cwl): Add unit test for starting and stopping LiveTailSession object. (aws#6110)

## Problem
The `LiveTailSession` object's start/stop methods aren't directly under
test. TailLogGroup tests are mocking their behavior. TailLogGroup
command tests are more focused on managing the session registry,
opening/writing to the document, and the close tab behaviors.

## Solution
Write a test that's scoped to creating a `session` and calling start and
stop on it. Assert that timers are handled/disposed of properly, and
that the session response stream is returned.

Addresses [this
comment](aws#6095 (comment)).

---

<!--- REMINDER: Ensure that your PR meets the guidelines in
CONTRIBUTING.md -->

License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

---------

Co-authored-by: Keegan Irby <[email protected]>

Author: 2 people

packages/core/src/awsService/cloudWatchLogs/registry/liveTailSession.ts

@@ -93,7 +93,7 @@ export class LiveTailSession {
         if (!commandOutput.responseStream) {
             throw new ToolkitError('LiveTail session response stream is undefined.')
         }
-        this.startTime = Date.now()
+        this.startTime = globals.clock.Date.now()
         this.endTime = undefined
         this.statusBarUpdateTimer = globals.clock.setInterval(() => {
             this.updateStatusBarItemText()
@@ -102,7 +102,7 @@ export class LiveTailSession {
     }
 
     public stopLiveTailSession() {
-        this.endTime = Date.now()
+        this.endTime = globals.clock.Date.now()
         this.statusBarItem.dispose()
         globals.clock.clearInterval(this.statusBarUpdateTimer)
         this.liveTailClient.abortController.abort()
@@ -116,7 +116,7 @@ export class LiveTailSession {
         }
         //Currently running
         if (this.endTime === undefined) {
-            return Date.now() - this.startTime
+            return globals.clock.Date.now() - this.startTime
         }
         return this.endTime - this.startTime
     }

packages/core/src/test/awsService/cloudWatchLogs/registry/liveTailSession.test.ts

@@ -2,17 +2,44 @@
  * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
  * SPDX-License-Identifier: Apache-2.0
  */
+import * as sinon from 'sinon'
+import * as FakeTimers from '@sinonjs/fake-timers'
 import assert from 'assert'
 import { LiveTailSession } from '../../../../awsService/cloudWatchLogs/registry/liveTailSession'
-import { StartLiveTailCommand } from '@aws-sdk/client-cloudwatch-logs'
+import {
+    CloudWatchLogsClient,
+    StartLiveTailCommand,
+    StartLiveTailResponseStream,
+} from '@aws-sdk/client-cloudwatch-logs'
 import { LogStreamFilterResponse } from '../../../../awsService/cloudWatchLogs/wizard/liveTailLogStreamSubmenu'
+import { installFakeClock } from '../../../testUtil'
 
 describe('LiveTailSession', async function () {
     const testLogGroupArn = 'arn:aws:test-log-group'
     const testRegion = 'test-region'
     const testFilter = 'test-filter'
     const testAwsCredentials = {} as any as AWS.Credentials
 
+    let sandbox: sinon.SinonSandbox
+    let clock: FakeTimers.InstalledClock
+
+    before(function () {
+        clock = installFakeClock()
+    })
+
+    beforeEach(function () {
+        clock.reset()
+        sandbox = sinon.createSandbox()
+    })
+
+    after(function () {
+        clock.uninstall()
+    })
+
+    afterEach(function () {
+        sandbox.restore()
+    })
+
     it('builds StartLiveTailCommand: no stream Filter, no event filter.', function () {
         const session = buildLiveTailSession({ type: 'all' }, undefined)
         assert.deepStrictEqual(
@@ -65,6 +92,36 @@ describe('LiveTailSession', async function () {
         )
     })
 
+    it('closes a started session', async function () {
+        const startLiveTailStub = sinon.stub(CloudWatchLogsClient.prototype, 'send').callsFake(function () {
+            return {
+                responseStream: mockResponseStream(),
+            }
+        })
+        const session = buildLiveTailSession({ type: 'all' }, testFilter)
+        assert.strictEqual(session.getLiveTailSessionDuration(), 0)
+
+        const returnedResponseStream = await session.startLiveTailSession()
+        assert.strictEqual(startLiveTailStub.calledOnce, true)
+        const requestArgs = startLiveTailStub.getCall(0).args
+        assert.deepEqual(requestArgs[0].input, session.buildStartLiveTailCommand().input)
+        assert.strictEqual(requestArgs[1].abortSignal !== undefined && !requestArgs[1].abortSignal.aborted, true)
+        assert.strictEqual(session.isAborted, false)
+        assert.strictEqual(clock.countTimers(), 1)
+        assert.deepStrictEqual(returnedResponseStream, mockResponseStream())
+
+        clock.tick(1000)
+        assert.strictEqual(session.getLiveTailSessionDuration(), 1000)
+
+        session.stopLiveTailSession()
+        assert.strictEqual(session.isAborted, true)
+        assert.strictEqual(clock.countTimers(), 0)
+
+        //Session is stopped; ticking the clock forward should not change the session duration
+        clock.tick(1000)
+        assert.strictEqual(session.getLiveTailSessionDuration(), 1000)
+    })
+
     function buildLiveTailSession(
         logStreamFilter: LogStreamFilterResponse,
         logEventFilterPattern: string | undefined
@@ -77,4 +134,16 @@ describe('LiveTailSession', async function () {
             awsCredentials: testAwsCredentials,
         })
     }
+
+    async function* mockResponseStream(): AsyncIterable<StartLiveTailResponseStream> {
+        const frame: StartLiveTailResponseStream = {
+            sessionUpdate: {
+                sessionMetadata: {
+                    sampled: false,
+                },
+                sessionResults: [],
+            },
+        }
+        yield frame
+    }
 })