Testing MOCHA and test duration

In the previous tutorial we looked at real live example code for mocha; this tutorial will examine the different test durations that exist and how we can test mocha.


Many reporters display test duration and then flag tests that are slow (default: 75ms), as shown below with the "spec" reporter:

test duration

Three levels of test duration exist (they are in the image below):

mocha thre levels of test duration
  1. FAST: All tests that run within half of the "slow" threshold shows the duration in green (if at all).
  2. NORMAL: All tests that run exceeding half of the threshold (but still within it) shows the duration in yellow.
  3. SLOW: All tests that run exceeding the threshold shows the duration in red.

If you want to change what is considered "slow", you can make use of the slow() method:

describe('something slow', function() {
  this.slow(300000); // five minutes

  it('it should take long enough for me to go make a sandwich', function() {
    // ...


For you to run Mocha's tests, you need either GNU Make or compatible; Cygwin should be sufficient.

  • You should cd to /path/to/mocha
  • Then run npm install
  • Finally run npm tes

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