How to run a single test with Mocha?

Question

I use Mocha to test my JavaScript stuff. My test file contains 5 tests. Is that possible to run a specific test (or set of tests) rather than all the tests in the file?

Answer 1

Try using mocha's --grep option:

    -g, --grep <pattern>            only run tests matching <pattern> 

You can use any valid JavaScript regex as <pattern>. For instance, if we have test/mytest.js:

it('logs a', function(done) {   console.log('a');   done(); });  it('logs b', function(done) {   console.log('b');   done(); }); 

Then:

$ mocha -g 'logs a' 

To run a single test. Note that this greps across the names of all describe(name, fn) and it(name, fn) invocations.

Consider using nested describe() calls for namespacing in order to make it easy to locate and select particular sets.

Answer 2

Depending on your usage pattern, you might just like to use only. We use the TDD style; it looks like this:

test.only('Date part of valid Partition Key', function (done) {     //... } 

Only this test will run from all the files/suites.