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CHANGELOG.md | ||
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README.md | ||
yui-coverage-comparison.md |
Istanbul - a JS code coverage tool written in JS
Features
- All-javascript instrumentation library that tracks statement, branch, and function coverage and reverse-engineers line coverage with 100% fidelity.
- Module loader hooks to instrument code on the fly
- Command line tools to run node unit tests "with coverage turned on" and no cooperation whatsoever from the test runner
- HTML, LCOV, Cobertura, TeamCity, and Clover reporting.
- Ability to use as middleware when serving JS files that need to be tested on the browser.
- Can be used on the command line as well as a library
- Based on the awesome
esprima
parser and the equally awesomeescodegen
code generator - Well-tested on node 0.4.x, 0.6.x, 0.8.x and the browser (instrumentation library only)
Installing
$ npm install -g istanbul
Getting started
The best way to see it in action is to run node unit tests. Say you have a test
script test.js
that runs all tests for your node project without coverage.
Simply:
$ cd /path/to/your/source/root
$ istanbul cover test.js
and this should produce a coverage.json
, lcov.info
and lcov-report/*html
under ./coverage
Sample of code coverage reports produced by this tool (for this tool!):
- HTML reports
- Standard LCOV reports (using
genhtml
on the lcov trace file)
Use cases
Supports the following use cases and more
- transparent coverage of nodejs unit tests
- ability to use in an
npm test
script for conditional coverage - instrumentation of files in batch mode for browser tests (using yeti for example)
- Server side code coverage for nodejs by embedding it as custom middleware
Ignoring code for coverage
- Skip an
if
orelse
path with/* istanbul ignore if */
or/* istanbul ignore else */
respectively. - For all other cases, skip the next 'thing' in the source with:
/* istanbul ignore next */
See ignoring-code-for-coverage.md for the spec.
The command line
$ istanbul help
gives you detailed help on all commands.
Usage: istanbul help
Available commands are:
check-coverage
checks overall coverage against thresholds from coverage JSON
files. Exits 1 if thresholds are not met, 0 otherwise
cover transparently adds coverage information to a node command. Saves
coverage.json and reports at the end of execution
help shows help
instrument
instruments a file or a directory tree and writes the
instrumented code to the desired output location
report writes reports for coverage JSON objects produced in a previous
run
test cover a node command only when npm_config_coverage is set. Use in
an `npm test` script for conditional coverage
Command names can be abbreviated as long as the abbreviation is unambiguous
The cover
command
$ istanbul cover my-test-script.js -- my test args
# note the -- between the command name and the arguments to be passed
The cover
command can be used to get a coverage object and reports for any arbitrary
node script. By default, coverage information is written under ./coverage
- this
can be changed using command-line options.
The cover
command can also be passed an optional --handle-sigint
flag to enable writing reports when a user triggers a manual SIGINT of the process that is being covered. This can be useful when you are generating coverage for a long lived process.
The test
command
The test
command has almost the same behavior as the cover
command, except that
it skips coverage unless the npm_config_coverage
environment variable is set.
This helps you set up conditional coverage for tests. In this case you would
have a package.json
that looks as follows.
{
"name": "my-awesome-lib",
"version": "1.0",
"script": {
"test": "istanbul test my-test-file.js"
}
}
Then:
$ npm test # will run tests without coverage
And:
$ npm test --coverage # will run tests with coverage
Note: This needs node 0.6
or better to work. npm
for node 0.4.x
does
not support the --coverage
flag.
The instrument
command
Instruments a single JS file or an entire directory tree and produces an output directory tree with instrumented code. This should not be required for running node unit tests but is useful for tests to be run on the browser (using yeti
for example).
The report
command
Writes reports using coverage*.json
files as the source of coverage information. Reports are available in the following formats:
- html - produces a bunch of HTML files with annotated source code
- lcovonly - produces an lcov.info file
- lcov - produces html + lcov files. This is the default format
- cobertura - produces a cobertura-coverage.xml file for easy Hudson integration
- text-summary - produces a compact text summary of coverage, typically to console
- text - produces a detailed text table with coverage for all files
- teamcity - produces service messages to report code coverage to TeamCity
- clover - produces a clover.xml file to integrate with Atlassian Clover
Additional report formats may be plugged in at the library level.
The check-coverage
command
Checks the coverage of statements, functions, branches, and lines against the provided thresholds. Postive thresholds are taken to be the minimum percentage required and negative numbers are taken to be the number of uncovered entities allowed.
Library usage
All the features of istanbul can be accessed as a library using its public API
Changelog
Changelog has been moved here.
License
istanbul is licensed under the BSD License.
Third-party libraries
The following third-party libraries are used by this module:
- abbrev: https://github.com/isaacs/abbrev-js - to handle command abbreviations
- async: https://github.com/caolan/async - for parallel instrumentation of files
- escodegen: https://github.com/Constellation/escodegen - for JS code generation
- esprima: https://github.com/ariya/esprima - for JS parsing
- fileset: https://github.com/mklabs/node-fileset - for loading and matching path expressions
- handlebars: https://github.com/wycats/handlebars.js/ - for report template expansion
- js-yaml: https://github.com/nodeca/js-yaml - for YAML config file load
- mkdirp: https://github.com/substack/node-mkdirp - to create output directories
- nodeunit: https://github.com/caolan/nodeunit - dev dependency for unit tests
- nopt: https://github.com/isaacs/nopt - for option parsing
- resolve: https://github.com/substack/node-resolve - for resolving a post-require hook module name into its main file.
- rimraf - https://github.com/isaacs/rimraf - dev dependency for unit tests
- which: https://github.com/isaacs/node-which - to resolve a node command to a file for the
cover
command - wordwrap: https://github.com/substack/node-wordwrap - for prettier help
- prettify: http://code.google.com/p/google-code-prettify/ - for syntax colored HTML reports. Files checked in under
lib/vendor/
Inspired by
- YUI test coverage - https://github.com/yui/yuitest - the grand-daddy of JS coverage tools. Istanbul has been specifically designed to offer an alternative to this library with an easy migration path.
- cover: https://github.com/itay/node-cover - the inspiration for the
cover
command, modeled after therun
command in that tool. The coverage methodology used by istanbul is quite different, however
Shout out to
- mfncooper - for great brainstorming discussions
- reid, davglass, the YUI dudes, for interesting conversations, encouragement, support and gentle pressure to get it done :)
Why the funky name?
Since all the good ones are taken. Comes from the loose association of ideas across coverage, carpet-area coverage, the country that makes good carpets and so on...