This is a plugin for gulp which runs Mocha tests in a separate process from
the gulp
process. Each time tests are run a new child process is created
meaning the test environment always starts cleanly, i.e., globals are reset as
are non-enumerable properties defined on native prototypes via
Object.defineProperty
. This also means that if your tests crash the node
process (e.g., process.exit(-1)
.) then an error
event is emitted rather than
your whole gulp
process crashing (good for watching).
Usage is according to this API:
stream.pipe(mocha({
// options
}))
This plugin uses mocha
version ^3.0.0
. The major version of this plugin will
match the major version of mocha
, which is a peer dependency of this plugin.
The plugin accepts these special options:
bin
: a path to amocha
executable to use instead of the one this plugin looks for by default. This is useful if you want to use a fork ofmocha
which goes by a different name or a different executable altogether.env
: the environment variables that the child process will have access to (key-value pairs, see child_process::fork). These variables are merged with your current environment variables and sent to the mocha executable.cwd
: the working directory for the child process. This can be used to put files that the test creates or reads from the working directory in a specific directory, instead of the directory where you are running gulp from.
All other options are properly prefixed with either -
or --
and passed to
the mocha
executable. Any arguments which do not take a value (e.g., c
,
colors
, or debug
) should just have a value of true
. Any arguments which
have dashes in the name can be specified by using camelCase (i.e., debugBrk
for --debug-brk
, inlineDiffs
for --inline-diffs
, etc) so you don't have
to use strings for the argument names. Please note that the gc
option must
be specified as exposeGc
(please see issue #21). For an example, see
this plugin's very own gulpfile.js
:
const DEBUG = process.env.NODE_ENV === 'debug',
CI = process.env.CI === 'true';
var gulp = require('gulp'),
mocha = require('./lib');
gulp.task('test', function () {
return gulp.src(['test/*.test.js'], {read: false})
.pipe(mocha({
debugBrk: DEBUG,
r: 'test/setup.js',
R: CI ? 'spec' : 'nyan',
istanbul: !DEBUG
}));
});
gulp.task('default', ['test'], function () {
gulp.watch('{lib,test}/*', ['test']);
});
With this setup the nyan
reporter will be used in development and the spec
reporter will be used in CI (Travis sets the CI
environment variable to
true
automatically).
The default
task will execute tests and watch for changes and execute tests
whenever a change is detected.
If the value of an argument is falsy (but not 0
) then it will not be passed
to mocha
. This is useful, for example, if you want to enable debugging only
when a certain environment variable is true. Example:
const DEBUG = process.env.NODE_ENV === 'debug';
stream.pipe(mocha({
debugBrk: DEBUG,
istanbul: !DEBUG
}));
As mentioned above an object provided underneath the env
options key will
allow you to specify a custom environment. This is useful, for example, to run
your tests in a different NODE_ENV than the default. Such a gulp task would
look like this:
var gulp = require('gulp'),
mocha = require('gulp-spawn-mocha');
gulp.task('test', function() {
return gulp
.src(['test/*.test.js'])
.pipe(mocha({
env: {'NODE_ENV': 'test'}
}));
});
These variables are merged with your current environment variables and sent to the mocha executable.
Because of the nature of this plugin launching an external process to run tests,
the standard coverage plugins for gulp will not work with this module. Starting
in version 0.4.0
Istanbul is included in order to enable code coverage
reports without having to instrument code on disk. You can use it by passing the
istanbul
option.
Set istanbul
to true
if you want to use all the default settings:
gulp.task('test', function() {
return gulp
.src(['test/*.test.js'])
.pipe(mocha({
istanbul: true
}));
});
This will launch a process equivilant to:
istanbul cover -- _mocha
The default settings of Istanbul output to a directory in the cwd
called
coverage
.
If you want to pass options to Istanbul, you can do that as well:
gulp.task('test', function() {
return gulp
.src(['test/*.test.js'])
.pipe(mocha({
istanbul: {
dir: 'path/to/custom/output/directory'
}
}));
});
This will launch a process equivilant to:
istanbul cover --dir path/to/custom/output/directory -- _mocha
This will output to a directory called path/to/custom/output/directory
.
Istanbul, like mocha
, supports a custom bin
option so you can use a custom
fork of Istanbul:
gulp.task('test', function() {
return gulp
.src(['test/*.test.js'])
.pipe(mocha({
istanbul: {
dir: 'path/to/custom/output/directory',
bin: require.resolve('isparta') + '/bin/isparta'
}
}));
});
This will launch a process equivilant to:
./node_modules/isparta/bin/isparta cover --dir path/to/custom/output/directory -- _mocha
Assuming you are using Travis for CI and Coveralls for
publishing code coverage reports it is very easy to automatically have Travis
publish to Coveralls when tests are run successfully. First make sure you
install and save the coveralls
module as a dev dependency:
npm i --save-dev coveralls
Then edit your .travis.yml
to have an after_success
command:
language: node_js
node_js:
- "0.11"
- "0.10"
after_success: ./node_modules/.bin/coveralls --verbose < coverage/lcov.info
The coveralls
module requires no additional configuration to publish to
Coveralls as long as both Travis and Coveralls are configured for the same
public repository. See node-coveralls
for more details.
You can pass output
option to write a report to a writeable stream. If
output
is a string then a writeable stream will be created with output
as
its path. Note, if you are using istanbul
, your reports content may contain
istanbul
's result.
Use file path:
gulp.task('test', function () {
return gulp.src(['test/*.test.js'], {read: false})
.pipe(mocha({
debugBrk: DEBUG,
r: 'test/setup.js',
R: CI ? 'spec' : 'nyan',
istanbul: !DEBUG,
output: 'result.log'
}));
});
Use file stream:
gulp.task('test', function () {
return gulp.src(['test/*.test.js'], {read: false})
.pipe(mocha({
debugBrk: DEBUG,
r: 'test/setup.js',
R: CI ? 'spec' : 'nyan',
istanbul: !DEBUG,
output: fs.createWriteStream('result.log', {flags: 'w'})
}));
});
The original gulp-mocha
is fine in most circumstances. If you need your
tests to run as a separate process (or a separate process is simply your
preference for the reasons specified above) or you need to use a custom
version of Mocha (e.g., a fork with bug fixes or custom functionality) then
you should use this plugin.