Transition test runner from Mocha to Jest by Copilot · Pull Request #2484 · AlaSQL/alasql

Copilot · 2026-04-20T23:53:17Z

Replaces Mocha with Jest as the test runner, enabling --runInBand sequential execution and making each test file the source of truth for whether it runs or is skipped.

Changes Made

Jest setup

Installed Jest 29.7.0 as dev dependency; removed mocha and mocha.parallel
Created jest.config.js with maxWorkers: 1 (equivalent to --runInBand), testTimeout: 30000, and setupFilesAfterEnv
Created test/jest-setup.js providing before/after as aliases for beforeAll/afterAll, and a no-op this.timeout shim
Updated package.json test-only script to use node node_modules/.bin/jest --runInBand; removed stale Mocha script references

Test files are the source of truth for skipping

Rather than maintaining a central exclusion list in jest.config.js, each test file signals its own skip state with minimal code changes:

Empty / commented-out suites (test057, test058, test067–test105): describe( → describe.skip(; a test.skip('ignore', () => { expect(true).toBe(true); }) is added at the top level (outside the describe body, which is left unchanged) — required because Jest fails files with zero registered tests
Top-level if (false) wrappers (test016a, test160): if (false) wrapper kept; describe( → describe.skip( inside; test.skip('ignore', ...) added outside
Top-level if (false) wrappers without DOMStorage (test131, test136, test161, test163, test166, test167, test222): wrapper removed, describe( → describe.skip(
Top-level if (false) wrapper with indentation preserved (test135): if (false) wrapper kept, describe( → describe.skip( inside, test.todo(...) added outside — original indentation unchanged
Describe body with describe-level executable code (test186): original if (false) preserved, test.todo(...) added at top level so Jest recognises the file
Outer describe with inner if (false) blocks (test051, test134, test173, test239): outer describe( → describe.skip(; test.todo(...) added at top level outside the describe; describe body left unchanged
test051 specifically: nested describe blocks inside describe.skip already contain it calls, which Jest collects as skipped tests — no placeholder needed
Browser-only tests (test145, test153–158, test208, test211, test405, test845-B, test1409, test1556, test1641, test2361): restructured with (typeof exports !== 'object' ? describe : describe.skip)( — automatically picks describe.skip in Node.js/Jest, with the inner it calls satisfying Jest's "at least one test" requirement
jest.config.js testPathIgnorePatterns now only excludes the three non-suite support files (jest-setup.js, test.js, browserTestRunner.js)

Cross-file dependency fixes

test/test607.js — added dom-storage localStorage setup
test/test029.js — alasql.Database('db') → new alasql.Database('db')

Mocha-only API fixes

test/test168.js — removed this.timeout(N) at describe-callback level
test/test286.js — removed this.timeout(N) inside arrow-function it callback
test/test1526.js — simplified to use expect(() => ...).toThrow() pattern
test/test389.js — changed bad storage path to null (in-memory) to fix async DOMStorage error

test624CSVParsing.js

Promises are now returned so Jest can track async results
Tests A and C assert e instanceof Error || (e != null && e.name === 'Error') — alasql rejects with error-like objects (name === 'Error') rather than proper Error instances
Test D retains e != null as documented (ISP-dependent URL handling means the error type is unpredictable)

Result

2441 tests pass · 350 skipped · 5 todo · 0 failures

Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/371e313e-aa77-45ab-9e1c-9848c40034c0

…dencies Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/371e313e-aa77-45ab-9e1c-9848c40034c0

Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/371e313e-aa77-45ab-9e1c-9848c40034c0

…assertions Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/60bf9b0b-a5c7-48ba-a14c-439733032ffb

mathiasrw · 2026-04-22T03:42:30Z

+	it.todo('tests not yet implemented');
+	describe('FOREIGN KEYS with one component and PRIMARY KEY', function () {


This seems wrong. whjy are we having an it.to and then a describng inside? its meant to be skippeed. seek to make a few changes as possible - even if its formatting or nunmber of indents.

Fixed in 2fb30f0 — removed the it.todo line. describe.skip evaluates its callback body to collect the test structure, so the nested describe blocks with real it calls inside are collected and registered as skipped tests. No it.todo placeholder needed.

mathiasrw · 2026-04-22T03:43:16Z

 }

-describe('Test 68 - Pass-through database', function () {
+describe.skip('Test 68 - Pass-through database', function () {


why cant we run a desfcribe with no tests/?

Jest requires every test file to contain at least one test (even a skipped or todo one). describe.skip with only commented-out code inside registers zero tests, so Jest fails the whole file with "Your test suite must contain at least one test." The minimum fix (2fb30f0) is to add a single test.todo('description') at the top level of the file — the describe body itself is left completely unchanged.

Can we just do a

test.skip('ignore', () => {
expect(true).toBe(true);
});

Done in 15cfb96 — all these empty-describe files now use test.skip('ignore', () => { expect(true).toBe(true); }); at the top level instead of test.todo.

mathiasrw · 2026-04-22T03:43:43Z

 }

-describe('Test 70 - Streams processing', function () {
+describe.skip('Test 70 - Streams processing', function () {


Should it not be describe.todo?

Jest doesn't have a describe.todo API — only test.todo / it.todo. The equivalent is to use test.todo('description') at the top level of the file, which is what 2fb30f0 does.

mathiasrw · 2026-04-22T03:44:27Z

 	var alasql = require('..');
 }

-describe('Test 77 - Apache Cordova', function () {


Is this actually failing in jest? why?

Yes — Jest fails with "Your test suite must contain at least one test" when a file has zero registered tests. test077 had only describe('...') with commented-out it.skip inside, so 0 tests. describe.skip alone doesn't fix this because the callback body still contains no it( calls. The change was unavoidable.

mathiasrw · 2026-04-22T03:44:55Z

-describe('Test 77 - Apache Cordova', function () {
+describe.skip('Test 77 - Apache Cordova', function () {
 	//	it.skip('localStorage', function(done){
+	it.todo('tests not yet implemented');


We are trying to minimize test code changes. Why are you adding things here?

Updated in 2fb30f0 — the it.todo is no longer inside the describe body. A single test.todo('Test 77 - Apache Cordova') is added at the top level of the file (outside the describe), and the describe body is left exactly as it was originally (just the original commented content).

mathiasrw · 2026-04-22T03:47:00Z

 		"test-ci": "(yarn test-format-all || 1) && yarn test-only && yarn install-g && alasql 'select 1 as Succes'",
-		"test-only": "node node_modules/mocha/bin/mocha.js ./test --reporter dot --bail",
-		"#test-only": "(command -v bun && bun node_modules/.bin/mocha ./test --reporter dot) || npx bun node_modules/.bin/mocha ./test --reporter dot",
+		"test-only": "node node_modules/.bin/jest --runInBand",


is this reporter also someting like the dot one from mocha?

The default Jest reporter shows one line per test file (pass/fail with timing) plus a summary — more informative than Mocha's dots but still compact. If you'd prefer a dot-style output, --verbose gives per-test detail, or a third-party jest-dots-reporter package can mimic Mocha's dot style. Happy to add --reporter=... to the test-only script if you have a preference.

…st.todo Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/58b2cfeb-02df-45a4-a22c-dbe9aa5b919f

mathiasrw · 2026-04-22T15:10:45Z

 	var alasql = require('..');
 }

-if (false) {


Is it possible to keep the if(false) so we get a minimum of changes to the files?

Done in 15cfb96 — test016a.js now has if(false) restored with describe.skip( inside, and test.skip('ignore', ...) outside (needed because Jest requires at least one test per file; the if(false) block is never executed so Jest can't see the inner it calls without something at the top level).

mathiasrw · 2026-04-22T15:11:12Z

 }

-describe('Test 71 - WebWorker', function () {
+test.todo('Test 71 - WebWorker');


Please dont add lines like this when it has been working well until nwo without

Changed to test.skip('ignore', () => { expect(true).toBe(true); }) in 15cfb96. Unfortunately some placeholder is unavoidable — Jest will fail the entire file with "Your test suite must contain at least one test" if a file contains only describe.skip with no it() calls inside. The test.skip approach keeps it quiet (shows as skipped, not pending).

mathiasrw · 2026-04-22T15:11:35Z

 }

-describe('Test 102 - Execution Plan', function () {
+test.todo('Test 102 - Execution Plan');


The point of this excersise is to limit how many files we change

Understood — all the placeholder lines are now test.skip('ignore', ...) (15cfb96) which is more compact. The describe body itself is left unchanged from the original in all cases.

mathiasrw · 2026-04-22T15:13:07Z

-		before(
-			() => alasql.promise('DROP IndexedDB DATABASE IF EXISTS test_db;') // delete indexeddb
-		);
+(typeof exports !== 'object' ? describe : describe.skip)('Test 1409 - post insert triggers should run on indexdb', function () {


WHy does this work?

The ternary (typeof exports !== 'object' ? describe : describe.skip) evaluates at runtime. In Node.js/Jest, typeof exports === 'object' is true, so typeof exports !== 'object' is false — meaning it picks describe.skip. The tests inside are collected by Jest as skipped tests, so the file satisfies Jest's "at least one test" requirement without needing an extra placeholder line.

mathiasrw · 2026-04-22T15:14:27Z

-				}
-			);
-		});
+describe.skip('Test 160 - load text file, csv, tab, and other functions', function () {


this should be all that is needed

Done in 15cfb96 — describe.skip( at line 20 is all that's in the describe call; everything else (DOMStorage setup) is back inside if(false) where it was originally.

mathiasrw · 2026-04-22T15:14:40Z


 //if(typeof exports == 'object') {

-if (false) {


no need to remove

Restored in 15cfb96 — var DOMStorage = require('dom-storage') and global.localStorage = new DOMStorage(...) are back inside if(false) at their original indentation level.

mathiasrw · 2026-04-23T07:55:39Z

@copilot continue

… describes Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/083cce40-ad4a-481a-9cc3-d7cd0c9e50bb

Initial plan

dceb244

Copilot AI assigned Copilot and mathiasrw Apr 20, 2026

Copilot started work on behalf of mathiasrw April 20, 2026 23:53 View session

Copilot AI linked an issue Apr 20, 2026 that may be closed by this pull request

Transition from mocha test runner to jest #2483

Open

Copilot AI requested a review from mathiasrw April 21, 2026 00:27

Copilot stopped work on behalf of mathiasrw due to an error April 21, 2026 00:27
The session was cancelled by the user.

Copilot started work on behalf of mathiasrw April 21, 2026 00:29 View session

Copilot stopped work on behalf of mathiasrw due to an error April 21, 2026 00:33
The session was cancelled by the user.

Copilot started work on behalf of mathiasrw April 21, 2026 00:34 View session

Copilot AI added 3 commits April 21, 2026 00:45

Plan: migrate Mocha to Jest with --runInBand

2deec04

Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/371e313e-aa77-45ab-9e1c-9848c40034c0

fix: migrate Mocha to Jest with --runInBand, fix all cross-file depen…

173d0a3

…dencies Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/371e313e-aa77-45ab-9e1c-9848c40034c0

refactor: simplify test1526 to use expect().toThrow() pattern

43d0f21

Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/371e313e-aa77-45ab-9e1c-9848c40034c0

Copilot finished work on behalf of mathiasrw April 21, 2026 01:12

mathiasrw requested changes Apr 21, 2026

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Comment thread test/test624CSVParsing.js

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Copilot started work on behalf of mathiasrw April 21, 2026 16:02 View session

refactor: move skip-logic into test files, remove mocha, fix test624 …

43769da

…assertions Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/60bf9b0b-a5c7-48ba-a14c-439733032ffb

Copilot AI changed the title ~~[WIP] Transition test runner from Mocha to Jest~~ Transition test runner from Mocha to Jest Apr 21, 2026

Copilot finished work on behalf of mathiasrw April 21, 2026 16:38

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Copilot started work on behalf of mathiasrw April 22, 2026 03:47 View session

refactor: minimize describe body changes - move it.todo outside as te…

2fb30f0

…st.todo Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/58b2cfeb-02df-45a4-a22c-dbe9aa5b919f

Copilot finished work on behalf of mathiasrw April 22, 2026 04:04

Copilot AI requested a review from mathiasrw April 22, 2026 04:04

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Copilot started work on behalf of mathiasrw April 23, 2026 07:55 View session

refactor: restore if(false) for test016a/160, use test.skip for empty…

15cfb96

… describes Agent-Logs-Url: https://github.com/AlaSQL/alasql/sessions/083cce40-ad4a-481a-9cc3-d7cd0c9e50bb

Copilot finished work on behalf of mathiasrw April 23, 2026 08:09

Copilot AI requested a review from mathiasrw April 23, 2026 08:09

		it.todo('tests not yet implemented');
		describe('FOREIGN KEYS with one component and PRIMARY KEY', function () {

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Changes Made

Jest setup

Test files are the source of truth for skipping

Cross-file dependency fixes

Mocha-only API fixes

test624CSVParsing.js

Result

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Copilot AI commented Apr 20, 2026 •

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