[FSSDK-12089] run tests in browser using vitest #1125

raju-opti · 2025-12-19T06:41:38Z

Summary

This PR configures running unit tests in browser using vitest. Tests can be run on browsers on local machine or on browserstack. A workflow job has been also added to run tests during CI runs.

Test plan

updated tests to work on browser

Issues

FSSDK-12089

coveralls · 2025-12-19T17:53:29Z

coverage: 77.745% (-0.007%) from 77.752%
when pulling b6ab39b on raju/browser_check
into f3933c0 on master.

Copilot

Pull request overview

This PR configures browser-based unit testing using Vitest, enabling tests to run on both local browsers and BrowserStack with support for multiple browser types (Chrome, Firefox, Edge, Safari). A new CI workflow job has been added to automate browser testing.

Added comprehensive Vitest browser configuration with BrowserStack integration and local browser fallback
Implemented custom Vitest plugins for request logging and console capture to improve debugging capabilities
Updated test mocks to be compatible with browser execution environment and refactored mock patterns for better compatibility

Reviewed changes

Copilot reviewed 23 out of 25 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
vitest.browser.config.mts	New browser test configuration with BrowserStack and local browser support
vitest.config.mts	Updated test file pattern to be more specific
vitest/request-logger-plugin.ts	Custom plugin for logging HTTP requests/responses during browser tests
vitest/console-capture-plugin.ts	Custom plugin for capturing and forwarding browser console logs to the test runner
public/console-capture.js	Client-side script for capturing browser console output and sending to server
scripts/run-browser-tests.js	Main orchestration script for running tests across different browser configurations
scripts/patch-vitest-viewport.js	Script to patch Vitest viewport commands for browser compatibility
lib/utils/cache/local_storage_cache.browser.spec.ts	Fixed test to sort keys before comparison for deterministic results
lib/project_config/project_config_manager.ts	Added blank line for readability
lib/project_config/project_config_manager.spec.ts	Updated test to provide error message to reject() call
lib/project_config/config_manager_factory.react_native.spec.ts	Changed async import to sync require for browser compatibility
lib/logging/logger_factory.spec.ts	Expanded mock to explicitly define all exported values for browser mode
lib/event_processor/event_processor_factory.spec.ts	Updated mocks to provide explicit constructor functions for browser compatibility
lib/event_processor/event_processor_factory.react_native.spec.ts	Changed async import to sync require for browser compatibility
lib/event_processor/event_processor_factory.browser.spec.ts	Refactored mocks to avoid importOriginal() which doesn't work in browser mode
lib/event_processor/batch_event_processor.spec.ts	Fixed mock setup and sorting logic for deterministic test behavior
lib/core/decision_service/index.ts	Made bucketer import path explicit with /index suffix
lib/core/decision_service/index.spec.ts	Refactored bucketer mock to use spy mode instead of hoisted mock
lib/core/bucketer/index.spec.ts	Updated mock pattern to use spy mode with proper MockInstance types
lib/core/audience_evaluator/index.spec.ts	Updated mock pattern to use spy mode with proper MockInstance types
lib/shared_types.ts	Changed regular imports to type imports for better tree-shaking and clarity
package.json	Added new dependencies for browser testing and updated nise version
.gitignore	Added .env to ignore list
.github/workflows/javascript.yml	Added browser_tests job to CI workflow with matrix strategy for multiple browsers

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public/console-capture.js

Copilot · 2025-12-19T17:54:20Z

lib/shared_types.ts

+  OdpManager, OdpSegmentApiManager,
+  OdpSegmentManager, OptimizelySegmentOption, RequestHandler


The reformatting of the export statement spreads multiple exports across a single line with inconsistent style. This reduces readability. Consider either keeping one export per line or using a more consistent multi-line format with proper indentation.

Suggested change

OdpManager, OdpSegmentApiManager,

OdpSegmentManager, OptimizelySegmentOption, RequestHandler

OdpManager,

OdpSegmentApiManager,

OdpSegmentManager,

OptimizelySegmentOption,

RequestHandler

Copilot · 2025-12-19T17:54:20Z

scripts/patch-vitest-viewport.js

+
+// This script patches files in node_modules/@vitest/browser, so it depends
+// on particular implementation details in that file. So, the @vitest/browser
+// vesion should be pinned in package.json devDependencies to avoid


Typo in comment: "vesion" should be "version".

Suggested change

// vesion should be pinned in package.json devDependencies to avoid

// version should be pinned in package.json devDependencies to avoid

Copilot · 2025-12-19T17:54:20Z

lib/core/bucketer/index.spec.ts

    );
  });

  it('should return decision response with variation null when a user is bucketed into a different grouped experiment than the one speicfied', () => {


Typo in comment: "speicfied" should be "specified".

Suggested change

it('should return decision response with variation null when a user is bucketed into a different grouped experiment than the one speicfied', () => {

it('should return decision response with variation null when a user is bucketed into a different grouped experiment than the one specified', () => {

Copilot · 2025-12-19T17:54:21Z

vitest/request-logger-plugin.ts

+        // @ts-ignore
+        res.write = function(chunk: any, ..._args: any[]) {
+          chunks.push(Buffer.from(chunk));
+          return true;
+        };
+
+        // @ts-ignore
+        res.end = function(chunk: any, ...args: any[]) {


The @ts-ignore directives are being used to suppress TypeScript errors when overriding the write and end methods. While this works, consider using proper type assertions or the safer @ts-expect-error directive which will error if the suppression becomes unnecessary in future TypeScript versions.

Copilot · 2025-12-19T17:54:21Z

vitest/console-capture-plugin.ts

+        // @ts-ignore
+        res.write = function(chunk: any, ..._args: any[]) {
+          chunks.push(Buffer.from(chunk));
+          return true;
+        };
+
+        // @ts-ignore


The @ts-ignore directives are being used to suppress TypeScript errors when overriding the write and end methods. While this works, consider using proper type assertions or the safer @ts-expect-error directive which will error if the suppression becomes unnecessary in future TypeScript versions.

Suggested change

// @ts-ignore

res.write = function(chunk: any, ..._args: any[]) {

chunks.push(Buffer.from(chunk));

return true;

};

// @ts-ignore

// @ts-expect-error

res.write = function(chunk: any, ..._args: any[]) {

chunks.push(Buffer.from(chunk));

return true;

};

// @ts-expect-error

Copilot · 2025-12-19T17:54:22Z

scripts/run-browser-tests.js

+}
+
+// BrowserStack Local is optional - only needed if tests require localhost access
+const useBrowserStackLocal = process.env.BROWSERSTACK_LOCAL === 'true';


Unused variable useBrowserStackLocal.

Suggested change

const useBrowserStackLocal = process.env.BROWSERSTACK_LOCAL === 'true';

Copilot · 2025-12-19T17:54:22Z

scripts/run-browser-tests.js

+let bs_local = null;
+
+function startTunnel() {
+  const username = process.env.BROWSERSTACK_USERNAME || process.env.BROWSER_STACK_USERNAME;


Unused variable username.

Suggested change

const username = process.env.BROWSERSTACK_USERNAME || process.env.BROWSER_STACK_USERNAME;

raju-opti added 14 commits December 9, 2025 19:31

init: basic working

27941cd

up

95aa8bc

playwright

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more

c3fdf53

up

f0c70aa

working

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saving

a7ceb67

export type fixes

7209622

more fixes

2e52f91

fix

228edc3

more fix

3b84e4a

cond_tree

89c42eb

all tests working on chrome

ebcfc81

check-working

5bebab9

optimizely-codereview-bot assigned raju-opti Dec 19, 2025

raju-opti added 13 commits December 19, 2025 16:26

working update

be93651

fix some unit tests

3d1323e

fix unit tests

7fc8897

firefox

faa2f61

cleanup 1

f40e13f

cleanup 2

4b0e5d0

ubuntu

2214243

rm

b633a03

comment

0a46360

logger

ce88f1e

upd

b593217

upd

2e8401c

updates

fdd3486

raju-opti changed the title ~~Raju/browser check~~ [FSSDK-12089] run tests in browser using vitest Dec 19, 2025

lint

677625f

raju-opti requested review from Copilot and junaed-optimizely December 19, 2025 17:51

Copilot started reviewing on behalf of raju-opti December 19, 2025 17:51 View session

Copilot AI reviewed Dec 19, 2025

View reviewed changes

raju-opti added 3 commits December 20, 2025 01:54

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		OdpManager, OdpSegmentApiManager,
		OdpSegmentManager, OptimizelySegmentOption, RequestHandler

	// vesion should be pinned in package.json devDependencies to avoid
	// version should be pinned in package.json devDependencies to avoid

	it('should return decision response with variation null when a user is bucketed into a different grouped experiment than the one speicfied', () => {
	it('should return decision response with variation null when a user is bucketed into a different grouped experiment than the one specified', () => {

[FSSDK-12089] run tests in browser using vitest #1125

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