🚀 Feature: Global fixtures should run before any files are loaded #4508

lucasrcosta · 2020-11-12T23:01:20Z

Prerequisites

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Checked next-gen ES issues and syntax problems by using the same environment and/or transpiler configuration without Mocha to ensure it isn't just a feature that actually isn't supported in the environment in question or a bug in your code.
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Ensured that there is no discrepancy between the locally and globally installed versions of Mocha. You can find them with: node node_modules/.bin/mocha --version(Local) and mocha --version(Global). We recommend that you not install Mocha globally.

Description

When using global fixtures, mocha loads the test files before running mochaGlobalSetup. This can cause issues when dependencies themselves load top-level configurations . But when --watch is passed, it works as expected.

This behavior differs from the following statements in the documentation:

Work identically parallel mode, watch mode, and serial mode
Now, before Mocha loads and runs your tests, it will execute the above global setup fixture, starting a server for testing.

Steps to Reproduce

fixtures.js

exports.mochaGlobalSetup = function() {
  console.log(`mochaGlobalSetup`);
}

test.js

console.log('Test file loaded')

it('runs', () => { })

Expected behavior:
Should run mochaGlobalSetup before loading the test files in all cases.

Actual behavior: [What actually happens]

> npx mocha -r fixtures.js test.js
Test file loaded
mochaGlobalSetup

  ✓ runs

  1 passing (3ms)

> npx mocha -r fixtures.js test.js --watch
mochaGlobalSetup
Test file loaded

  ✓ runs

  1 passing (2ms)

ℹ [mocha] waiting for changes...

Reproduces how often: 100%

Versions

node --version: Unknown command: mocha
node node_modules/.bin/mocha --version: 8.2.1
node --version: v10.22.1
Your operating system: macOS Catalina 10.15.7 64bit
Your shell (e.g., bash, zsh, PowerShell, cmd): fish

The text was updated successfully, but these errors were encountered:

boneskull · 2020-11-13T19:30:27Z

This is intended behavior, but

the documentation is correct in that the fixtures are run before your tests
it is incorrect in that the fixtures are not run before your test files load

the reason it is the way it is: it'd otherwise be unusable in a browser without adding more API surface, and we try to keep things the same between node/browser as much as possible.

this will be a problem if we allow async suites, since the suites would potentially try to use a resource (e.g. connect to a port) that a global setup fixture created... hm.

two questions:

does this behavior prevent you from using global fixtures?
if you used it as it works now, and we changed global setup fixtures to run before the test files are loaded, would that break what you're doing?

BREAKING CHANGE `Mocha#run()` was orchestrating if and when to run global setup/teardown fixtures, but `Mocha#run()` must be called after test files have been loaded. This is a problem, because: 1. `--delay` may expect something created in a fixture to be accessible, but it won't be 2. Any future support for async suites is similarly negatively impacted 3. It was inconsistent between "watch" and "single run" mode; "watch" mode already has this behavior! This change causes setup fixtures to run _before_ any test files have been loaded. In Node.js, this happens in `lib/cli/run-helpers`. - Added two functions to `Mocha`; `Mocha#globalSetupEnabled()` and `Mocha#globalTeardownEnabled()` which both return booleans - Correct order of operations is asserted in `test/integration/global-fixtures.spec.js` - Removed low-value (and newly broken) unit tests where `Mocha#run` called `runGlobalSetup`/`runGlobalTeardown` - Add a note to `browser-entry.js` about global fixtures This is breaking because: 1. Browser users now must run setup/teardown fixtures manually. 2. Somebody's test harness might expect test files to be loaded (and suites run) _before_ global setup fixtures execute.

boneskull · 2020-11-13T21:13:23Z

I've created #4511 to address this. I agree that the behavior should change. Hopefully there hasn't been too much adoption of the feature yet..

lucasrcosta · 2020-11-13T23:34:23Z

@boneskull thank you for addressing this.

does this behavior prevent you from using global fixtures?

It does, since the test files are loaded before the fixtures. I'm working in a codebase that loads configurations from a database before importing the files to start a webserver. Some of it's dependencies use these configurations on top-level code (regardless of wether that's good practice or not), so today I cannot push global fixtures to the code since it would break the CI workflow.

if you used it as it works now, and we changed global setup fixtures to run before the test files are loaded, would that break what you're doing?

No, in fact the behavior on watch mode is exactly that, so I've been developing that way the last few days. I understand I'll have to revert the introduction of global fixtures and wait for this to be finished in order to adopt it.

By the way, this is a great feature and it makes the test setup process so much clearer. Specially if you can delay the files being loaded, so that all code can be in the proper place. Congratulations.

SgtPooki · 2020-11-25T23:14:48Z

I left a comment saying the setup and teardown functions weren't being called for me, they are.. I was doing

exports = {
    mochaGlobalSetup,
    mochaGlobalTeardown,
    mochaHooks,
};

instead of

exports.mochaGlobalSetup = mochaGlobalSetup;
exports.mochaGlobalTeardown = mochaGlobalTeardown;
exports.mochaHooks = mochaHooks;

too used to typescript ¯_(ツ)_/¯. Hopefully leaving this comment helps someone else?

witrin · 2021-11-01T12:34:21Z

Without this patch we were currently not able to perform integration tests for one of our bigger systems in a clean and lean way. We really hope for a merge here. Because 9 is already released.

witrin · 2021-12-17T21:05:05Z

@boneskull How is the planing about this?

mariobm · 2022-04-26T11:40:04Z

This feature would be a game-changer for me. It's really needed.

justinasfour04 · 2022-07-27T15:29:56Z

what is the status on this? I need this fix in version 8.2.0

justinasfour04 · 2022-07-29T18:01:30Z

This issue is 2 years old, does anyone have a work-around?

codembark · 2023-12-10T00:42:03Z

This prevents me from using global fixtures to set up integration tests. My use case is starting a database before importing a server module in the test file which requires the database to exist. I'll have to find another work around in the meantime.

Appreciate all the hard work you folks put into Mocha!

lucasrcosta added the unconfirmed-bug label Nov 12, 2020

boneskull added area: documentation anything involving docs or mochajs.org status: waiting for author waiting on response from OP - more information needed area: usability concerning user experience or interface and removed unconfirmed-bug labels Nov 13, 2020

boneskull changed the title ~~Global fixtures loading tests before mochaGlobalSetup~~ global fixtures should run before any files are loaded Nov 13, 2020

boneskull linked a pull request Nov 13, 2020 that will close this issue

run global setup before test files load; closes #4508 #4511

Open

boneskull added the semver-major implementation requires increase of "major" version number; "breaking changes" label Nov 13, 2020

Abe27342 mentioned this issue Jun 8, 2023

Provide different layers' APIs to describeCompat suites microsoft/FluidFramework#15917

Merged

JoshuaKGoldberg added status: accepting prs Mocha can use your help with this one! and removed status: waiting for author waiting on response from OP - more information needed labels Dec 28, 2023

JoshuaKGoldberg changed the title ~~global fixtures should run before any files are loaded~~ 🚀 Feature: global fixtures should run before any files are loaded Dec 28, 2023

JoshuaKGoldberg changed the title ~~🚀 Feature: global fixtures should run before any files are loaded~~ 🚀 Feature: Global fixtures should run before any files are loaded Dec 28, 2023

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🚀 Feature: Global fixtures should run before any files are loaded #4508

🚀 Feature: Global fixtures should run before any files are loaded #4508

lucasrcosta commented Nov 12, 2020 •

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boneskull commented Nov 13, 2020 •

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boneskull commented Nov 13, 2020

lucasrcosta commented Nov 13, 2020 •

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SgtPooki commented Nov 25, 2020

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mariobm commented Apr 26, 2022

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justinasfour04 commented Jul 29, 2022

codembark commented Dec 10, 2023 •

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🚀 Feature: Global fixtures should run before any files are loaded #4508

🚀 Feature: Global fixtures should run before any files are loaded #4508

Comments

lucasrcosta commented Nov 12, 2020 • edited Loading

Prerequisites

Description

Steps to Reproduce

Versions

boneskull commented Nov 13, 2020 • edited Loading

boneskull commented Nov 13, 2020

lucasrcosta commented Nov 13, 2020 • edited Loading

SgtPooki commented Nov 25, 2020

witrin commented Nov 1, 2021

witrin commented Dec 17, 2021 • edited Loading

mariobm commented Apr 26, 2022

justinasfour04 commented Jul 27, 2022 • edited Loading

justinasfour04 commented Jul 29, 2022

codembark commented Dec 10, 2023 • edited Loading

lucasrcosta commented Nov 12, 2020 •

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boneskull commented Nov 13, 2020 •

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lucasrcosta commented Nov 13, 2020 •

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witrin commented Dec 17, 2021 •

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justinasfour04 commented Jul 27, 2022 •

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codembark commented Dec 10, 2023 •

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