Prerequisites

• Checked that your issue hasn't already been filed by cross-referencing issues with the faq label
• 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.
• 'Smoke tested' the code to be tested by running it outside the real test suite to get a better sense of whether the problem is in the code under test, your usage of Mocha, or Mocha itself
• 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