tests: explicitly set TZ for local tests (#4304)

In #4297 we explicitly set the TZ in a part of the
code that CI uses, but when running the unit tests locally
it does not trigger that part of the code.

Due to this the tests still fail when run locally.

Solution:

Add the TZ assignment to a part of the code when unit tests
are running locally. Now unit tests will pass when run locally

Signed-off-by: nkomonen <[email protected]>

Author: nkomonen-amazon

scripts/test/launchTestUtilities.ts

@@ -11,10 +11,6 @@ import { runTests } from '@vscode/test-electron'
 import { VSCODE_EXTENSION_ID } from '../../src/shared/extensions'
 import { TestOptions } from '@vscode/test-electron/out/runTest'
 
-// Set a fixed timezone. Intentionally _not_ UTC, to increase variation in tests.
-process.env.TZ = 'US/Pacific'
-// process.env.TZ = 'Europe/London'
-
 const envvarVscodeTestVersion = 'VSCODE_TEST_VERSION'
 
 const stable = 'stable'

src/test/cloudWatchLogs/registry/logDataRegistry.test.ts

@@ -210,7 +210,11 @@ describe('LogDataRegistry', async function () {
         it('matches CloudWatch insights timestamps', function () {
             const time = 1624201162222 // 2021-06-20 14:59:22.222 GMT+0
             const timestamp = formatDateTimestamp(true, new Date(time))
-            assert.strictEqual(timestamp, '2021-06-20T14:59:22.222-07:00')
+            assert.strictEqual(
+                timestamp,
+                '2021-06-20T14:59:22.222-07:00',
+                '`process.env.TZ` assignment may have been modified'
+            )
         })
     })
 })

src/test/testRunner.ts

@@ -9,6 +9,12 @@ import Mocha from 'mocha'
 import glob from 'glob'
 import * as fs from 'fs-extra'
 
+// Set explicit timezone to ensure that tests run locally do not use the user's actual timezone, otherwise
+// the test can pass on one persons machine but not anothers.
+// Intentionally _not_ UTC, to increase variation in tests.
+// process.env.TZ = 'Europe/London'
+process.env.TZ = 'US/Pacific'
+
 /**
  * @param initTests List of relative paths to test files containing root hooks: https://mochajs.org/#available-root-hooks
  */