Mocha Configuration Spec Property Issue

[X-Guardian]

Currently, I believe the test runner requires a Mocha configuration file (.mocharc.js etc) to contain/export a spec property with an array of test file globs to allow the runner to discover all the test files within a project.

There is a problem with specifying a spec property within the Mocha configuration file, in that as it is an array, it is a mergeable option and therefore cannot be overridden on the command line, only added to. See https://mochajs.org/next/running/configuring/#merging.

This means that with this configuration, I cannot run mocha from the command line, targeting an individual spec file for example, without having to temporarily comment out the spec property, or to use multiple config files.

Would it be possible to either have the option to specify a custom Mocha config file from within the runner, or be able to specify the spec array in the runner, rather than requiring it in the config?

[Danielku15]

Hmm, not sure if I understand you correctly but generally things work like this:

The mocha-vscode extension respects the contents of the mocha configuration. e.g. it would only list tests from files already included via the configuration file. It

When the extension launches tests, it specifies multiple things:

• It specifies the config to use via --config
• It changes the reporter to be able to recieve the test details via --reporter
• It first excludes all tests from being executed via --ignore **/*.*
• It then re-adds the files to be considered via --file
• It additionally filters the individual tests to execute via --grep

This eventually should ensure that exactly the tests are executed as expected. There is still a small chance of misbehavior if you have the same test names in multiple files and execute partially overlapping things.

Unfortunately Mocha doesn't provide a very deterministic way to pass in exactly the tests you want to run, that's why the extension has the mentioned mechanism.

The loading of the configuration happens through Mocha APIs which should take care of merging configs.

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Coming back to your point. It is intentional that you cannot run tests which are not included in the .mocharc configs. If you have some very specific scenario it might be better to setup an example project to show your expectation. If you think it's a bug or missing feature, I'd recommend that you fill out the respective issue template to have all details available