refactor(logger): use vitest env helpers in unit tests (#4360)

Co-authored-by: David <75678655+David-Werth@users.noreply.github.com>
Co-authored-by: Swopnil Dangol <swopnildangol@gmail.com>

Author: dwrth

packages/logger/tests/unit/formatters.test.ts

@@ -1,5 +1,13 @@
 import { AssertionError } from 'node:assert';
-import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest';
+import {
+  afterAll,
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  vi,
+} from 'vitest';
 import { PowertoolsLogFormatter } from '../../src/formatter/PowertoolsLogFormatter.js';
 import {
   LogFormatter,
@@ -53,13 +61,8 @@ const unformattedAttributes: UnformattedAttributes = {
   },
 };
 
-process.env.POWERTOOLS_DEV = 'true';
-
-const logger = new Logger();
-
 const jsonReplacerFn: CustomJsonReplacerFn = (_: string, value: unknown) =>
   value instanceof Set ? [...value] : value;
-const loggerWithReplacer = new Logger({ jsonReplacerFn });
 
 /**
  * A custom log formatter that formats logs using only the message, log level as a number, and timestamp.
@@ -90,15 +93,19 @@ class CustomFormatter extends LogFormatter {
     );
   }
 }
-const loggerWithCustomLogFormatter = new Logger({
-  logFormatter: new CustomFormatter(),
-});
 
 describe('Formatters', () => {
-  const ENVIRONMENT_VARIABLES = process.env;
+  // Ensure dev mode is on for logger initialization
+  vi.stubEnv('POWERTOOLS_DEV', 'true');
+  const logger = new Logger();
+  const loggerWithReplacer = new Logger({ jsonReplacerFn });
+  const loggerWithCustomLogFormatter = new Logger({
+    logFormatter: new CustomFormatter(),
+  });
+  vi.unstubAllEnvs();
 
   beforeEach(() => {
-    process.env = { ...ENVIRONMENT_VARIABLES };
+    vi.stubEnv('POWERTOOLS_DEV', 'true');
     const mockDate = new Date(1466424490000);
     vi.useFakeTimers().setSystemTime(mockDate);
     vi.clearAllMocks();
@@ -109,6 +116,10 @@ describe('Formatters', () => {
     vi.useRealTimers();
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   // #region base log keys
 
   it('formats the base log keys', () => {
@@ -451,8 +462,7 @@ describe('Formatters', () => {
 
   it('formats stack as string when not in dev mode', () => {
     // Prepare
-    const originalDevMode = process.env.POWERTOOLS_DEV;
-    delete process.env.POWERTOOLS_DEV; // Ensure dev mode is off
+    vi.stubEnv('POWERTOOLS_DEV', 'false'); // Ensure dev mode is off
 
     const error = new Error('Test error');
     const formatter = new PowertoolsLogFormatter();
@@ -463,9 +473,6 @@ describe('Formatters', () => {
     // Assess
     expect(formattedError.stack).toEqual(expect.any(String));
     expect(Array.isArray(formattedError.stack)).toBe(false);
-
-    // Cleanup
-    process.env.POWERTOOLS_DEV = originalDevMode;
   });
 
   it('formats custom errors by including only enumerable properties', () => {
@@ -528,7 +535,7 @@ describe('Formatters', () => {
 
   it('formats the timestamp to ISO 8601, accounting for the `America/New_York` timezone offset', () => {
     // Prepare
-    process.env.TZ = 'America/New_York';
+    vi.stubEnv('TZ', 'America/New_York');
     /*
       Difference between UTC and `America/New_York`(GMT -04.00) is 240 minutes.
       The positive value indicates that `America/New_York` is behind UTC.
@@ -544,7 +551,7 @@ describe('Formatters', () => {
 
   it('formats the timestamp to ISO 8601 with correct milliseconds for `America/New_York` timezone', () => {
     // Prepare
-    process.env.TZ = 'America/New_York';
+    vi.stubEnv('TZ', 'America/New_York');
     /*
       Difference between UTC and `America/New_York`(GMT -04.00) is 240 minutes.
       The positive value indicates that `America/New_York` is behind UTC.
@@ -560,7 +567,7 @@ describe('Formatters', () => {
 
   it('formats the timestamp to ISO 8601, adjusting for `America/New_York` timezone, preserving milliseconds and accounting for date change', () => {
     // Prepare
-    process.env.TZ = 'America/New_York';
+    vi.stubEnv('TZ', 'America/New_York');
     /*
       Difference between UTC and `America/New_York`(GMT -04.00) is 240 minutes.
       The positive value indicates that `America/New_York` is behind UTC.
@@ -576,7 +583,7 @@ describe('Formatters', () => {
 
   it('it formats the timestamp to ISO 8601 with correct milliseconds for `Asia/Dhaka` timezone', () => {
     // Prepare
-    process.env.TZ = 'Asia/Dhaka';
+    vi.stubEnv('TZ', 'Asia/Dhaka');
     vi.setSystemTime(new Date('2016-06-20T12:08:10.910Z'));
     /*
       Difference between UTC and `Asia/Dhaka`(GMT +06.00) is 360 minutes.
@@ -594,7 +601,7 @@ describe('Formatters', () => {
 
   it('formats the timestamp to ISO 8601, adjusting for `Asia/Dhaka` timezone, preserving milliseconds and accounting for date change', () => {
     // Prepare
-    process.env.TZ = 'Asia/Dhaka';
+    vi.stubEnv('TZ', 'Asia/Dhaka');
     const mockDate = new Date('2016-06-20T20:08:10.910Z');
     vi.setSystemTime(mockDate);
     /*
@@ -613,7 +620,7 @@ describe('Formatters', () => {
 
   it('returns defaults to :UTC when an env variable service is not set', () => {
     // Prepare
-    process.env.TZ = undefined;
+    vi.stubEnv('TZ', undefined);
 
     vi.spyOn(Date.prototype, 'getTimezoneOffset').mockReturnValue(-360);
     const formatter = new PowertoolsLogFormatter();
@@ -627,7 +634,7 @@ describe('Formatters', () => {
 
   it('defaults to :UTC when the TZ env variable is set to :/etc/localtime', () => {
     // Prepare
-    process.env.TZ = ':/etc/localtime';
+    vi.stubEnv('TZ', ':/etc/localtime');
     vi.spyOn(Date.prototype, 'getTimezoneOffset').mockReturnValue(0);
     const formatter = new PowertoolsLogFormatter();
 

packages/logger/tests/unit/initializeLogger.test.ts

@@ -1,18 +1,28 @@
-import { beforeEach, describe, expect, it, type Mock, vi } from 'vitest';
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  type Mock,
+  vi,
+} from 'vitest';
 import { LogJsonIndent, LogLevel } from '../../src/constants.js';
 import { Logger } from '../../src/Logger.js';
 
 describe('Log levels', () => {
-  const ENVIRONMENT_VARIABLES = process.env;
-
   beforeEach(() => {
-    process.env = { ...ENVIRONMENT_VARIABLES, POWERTOOLS_DEV: 'true' };
+    vi.stubEnv('POWERTOOLS_DEV', 'true');
     vi.clearAllMocks();
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('uses the default service name when none is provided', () => {
     // Prepare
-    process.env.POWERTOOLS_SERVICE_NAME = undefined;
+    vi.stubEnv('POWERTOOLS_SERVICE_NAME', undefined);
     const logger = new Logger();
 
     // Act
@@ -28,7 +38,7 @@ describe('Log levels', () => {
 
   it('uses service name specified in environment variables', () => {
     // Prepare
-    process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
+    vi.stubEnv('POWERTOOLS_SERVICE_NAME', 'hello-world');
     const logger = new Logger();
 
     // Act
@@ -44,7 +54,7 @@ describe('Log levels', () => {
 
   it('uses service name specified in the constructor', () => {
     // Prepare
-    process.env.POWERTOOLS_SERVICE_NAME = undefined;
+    vi.stubEnv('POWERTOOLS_SERVICE_NAME', undefined);
     const logger = new Logger({ serviceName: 'hello-world' });
 
     // Act
@@ -60,7 +70,7 @@ describe('Log levels', () => {
 
   it('overrides the service name when creating a child logger', () => {
     // Prepare
-    process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
+    vi.stubEnv('POWERTOOLS_SERVICE_NAME', 'hello-world');
     const logger = new Logger();
     const childLogger = logger.createChild({ serviceName: 'child-service' });
 
@@ -127,7 +137,7 @@ describe('Log levels', () => {
 
   it("doesn't use the global console object by default", () => {
     // Prepare
-    process.env.POWERTOOLS_DEV = undefined;
+    vi.stubEnv('POWERTOOLS_DEV', undefined);
     const logger = new Logger();
 
     // Assess

packages/logger/tests/unit/injectLambdaContext.test.ts

@@ -1,7 +1,7 @@
 import context from '@aws-lambda-powertools/testing-utils/context';
 import middy from '@middy/core';
 import type { Context } from 'aws-lambda';
-import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { search } from '../../src/correlationId.js';
 import { Logger } from '../../src/Logger.js';
 import { injectLambdaContext } from '../../src/middleware/middy.js';
@@ -20,16 +20,15 @@ const getContextLogEntries = (overrides?: Record<string, unknown>) => ({
 });
 
 describe('Inject Lambda Context', () => {
-  const ENVIRONMENT_VARIABLES = process.env;
-
   beforeEach(() => {
-    process.env = {
-      ...ENVIRONMENT_VARIABLES,
-      POWERTOOLS_DEV: 'true',
-    };
+    vi.stubEnv('POWERTOOLS_DEV', 'true');
     vi.clearAllMocks();
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('adds the context to log messages when the feature is enabled', () => {
     // Prepare
     const logger = new Logger();

packages/logger/tests/unit/logBuffer.test.ts

@@ -1,22 +1,29 @@
 import context from '@aws-lambda-powertools/testing-utils/context';
 import type { Context } from 'aws-lambda';
 import middy from 'middy5';
-import { beforeEach, describe, expect, it, type Mock, vi } from 'vitest';
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  type Mock,
+  vi,
+} from 'vitest';
 import { LogLevel, UncaughtErrorLogMessage } from '../../src/constants.js';
 import { Logger } from '../../src/Logger.js';
 import { injectLambdaContext } from '../../src/middleware/middy.js';
 
 describe('Buffer logs', () => {
-  const ENVIRONMENT_VARIABLES = process.env;
-
   beforeEach(() => {
-    process.env = {
-      ...ENVIRONMENT_VARIABLES,
-      POWERTOOLS_DEV: 'true',
-    };
+    vi.stubEnv('POWERTOOLS_DEV', 'true');
     vi.clearAllMocks();
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('does not buffer logs when disabled', () => {
     // Prepare
     const logger = new Logger({
@@ -94,7 +101,7 @@ describe('Buffer logs', () => {
 
   it('outputs a warning when the Advanced Logging Configuration Log Level is less verbose than the Log Buffering Log Level', () => {
     // Assemble
-    process.env.AWS_LAMBDA_LOG_LEVEL = 'INFO';
+    vi.stubEnv('AWS_LAMBDA_LOG_LEVEL', 'INFO');
     const logger = new Logger({
       logLevel: LogLevel.DEBUG,
       logBufferOptions: { enabled: true, bufferAtVerbosity: 'DEBUG' },
@@ -116,7 +123,7 @@ describe('Buffer logs', () => {
 
   it('When the buffer is flushed it outputs a warning if the Advanced Logging Configuration Log Level is less verbose than the Log Buffering Log Level', () => {
     // Assemble
-    process.env.AWS_LAMBDA_LOG_LEVEL = 'INFO';
+    vi.stubEnv('AWS_LAMBDA_LOG_LEVEL', 'INFO');
     const logger = new Logger({
       logLevel: LogLevel.DEBUG,
       logBufferOptions: { enabled: true, bufferAtVerbosity: 'DEBUG' },
@@ -195,7 +202,7 @@ describe('Buffer logs', () => {
 
   it('does not output buffered logs when trace id is not set', () => {
     // Prepare
-    process.env._X_AMZN_TRACE_ID = undefined;
+    vi.stubEnv('_X_AMZN_TRACE_ID', undefined);
     const logger = new Logger({ logBufferOptions: { enabled: true } });
 
     // Act
@@ -210,7 +217,7 @@ describe('Buffer logs', () => {
 
   it('it safely short circuits when clearBuffer is called without a trace id', () => {
     // Prepare
-    process.env._X_AMZN_TRACE_ID = undefined;
+    vi.stubEnv('_X_AMZN_TRACE_ID', undefined);
     const logger = new Logger({
       logLevel: LogLevel.ERROR,
       logBufferOptions: { enabled: true, bufferAtVerbosity: LogLevel.DEBUG },

packages/logger/tests/unit/logEvent.test.ts

@@ -1,7 +1,7 @@
 import context from '@aws-lambda-powertools/testing-utils/context';
 import middy from '@middy/core';
 import type { Context } from 'aws-lambda';
-import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { Logger } from '../../src/Logger.js';
 import { injectLambdaContext } from '../../src/middleware/middy.js';
 
@@ -10,17 +10,16 @@ const event = {
 };
 
 describe('Log event', () => {
-  const ENVIRONMENT_VARIABLES = process.env;
-
   beforeEach(() => {
-    process.env = {
-      ...ENVIRONMENT_VARIABLES,
-      POWERTOOLS_LOGGER_LOG_EVENT: 'true',
-      POWERTOOLS_DEV: 'true',
-    };
+    vi.stubEnv('POWERTOOLS_LOGGER_LOG_EVENT', 'true');
+    vi.stubEnv('POWERTOOLS_DEV', 'true');
     vi.clearAllMocks();
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('logs the event with the correct log level and message', () => {
     // Prepare
     const logger = new Logger();
@@ -35,7 +34,7 @@ describe('Log event', () => {
 
   it("doesn't log the event when the feature is disabled", () => {
     // Prepare
-    process.env.POWERTOOLS_LOGGER_LOG_EVENT = 'false';
+    vi.stubEnv('POWERTOOLS_LOGGER_LOG_EVENT', 'false');
     const logger = new Logger();
 
     // Act
@@ -112,7 +111,7 @@ describe('Log event', () => {
 
   it('prefers the local logEvent configuration over the environment variable', async () => {
     // Prepare
-    process.env.POWERTOOLS_LOGGER_LOG_EVENT = 'false';
+    vi.stubEnv('POWERTOOLS_LOGGER_LOG_EVENT', 'false');
     const logger = new Logger();
     const handler = middy(async () => {}).use(
       injectLambdaContext(logger, { logEvent: true })
@@ -127,7 +126,7 @@ describe('Log event', () => {
 
   it('passes down the log event configuration to child loggers', () => {
     // Prepare
-    process.env.POWERTOOLS_LOGGER_LOG_EVENT = 'false';
+    vi.stubEnv('POWERTOOLS_LOGGER_LOG_EVENT', 'false');
     const logger = new Logger();
     const childLogger = logger.createChild();