code coverage

coverify

A simple way to check code coverage in browserify is to use the coverify transform.

$ browserify -t coverify test/*.js | node | coverify

or to run your tests in a real browser:

$ browserify -t coverify test/*.js | testling | coverify

coverify works by transforming the source of each package so that each expression is wrapped in a __coverageWrap() function.

Each expression in the program gets a unique ID and the __coverageWrap() function will print COVERED $FILE $ID the first time the expression is executed.

Before the expressions run, coverify prints a COVERAGE $FILE $NODES message to log the expression nodes across the entire file as character ranges.

Here's what the output of a full run looks like:

$ browserify -t coverify test/whatever.js | nodeCOVERAGE "/home/substack/projects/defined/test/whatever.js" [[14,28],[14,28],[0,29],[41,56],[41,56],[30,57],[95,104],[95,105],[126,146],[126,146],[115,147],[160,194],[160,194],[152,195],[200,217],[200,218],[76,220],[59,221],[59,222]]COVERED "/home/substack/projects/defined/test/whatever.js" 2COVERED "/home/substack/projects/defined/test/whatever.js" 1COVERED "/home/substack/projects/defined/test/whatever.js" 0COVERAGE "/home/substack/projects/defined/index.js" [[48,49],[55,71],[51,71],[73,76],[92,104],[92,118],[127,139],[120,140],[172,195],[172,196],[0,204],[0,205]]COVERED "/home/substack/projects/defined/index.js" 11COVERED "/home/substack/projects/defined/index.js" 10COVERED "/home/substack/projects/defined/test/whatever.js" 5COVERED "/home/substack/projects/defined/test/whatever.js" 4COVERED "/home/substack/projects/defined/test/whatever.js" 3COVERED "/home/substack/projects/defined/test/whatever.js" 18COVERED "/home/substack/projects/defined/test/whatever.js" 17COVERED "/home/substack/projects/defined/test/whatever.js" 16TAP version 13# whateverCOVERED "/home/substack/projects/defined/test/whatever.js" 7COVERED "/home/substack/projects/defined/test/whatever.js" 6COVERED "/home/substack/projects/defined/test/whatever.js" 10COVERED "/home/substack/projects/defined/test/whatever.js" 9COVERED "/home/substack/projects/defined/test/whatever.js" 8COVERED "/home/substack/projects/defined/test/whatever.js" 13COVERED "/home/substack/projects/defined/test/whatever.js" 12COVERED "/home/substack/projects/defined/test/whatever.js" 11COVERED "/home/substack/projects/defined/index.js" 0COVERED "/home/substack/projects/defined/index.js" 2COVERED "/home/substack/projects/defined/index.js" 1COVERED "/home/substack/projects/defined/index.js" 5COVERED "/home/substack/projects/defined/index.js" 4COVERED "/home/substack/projects/defined/index.js" 3COVERED "/home/substack/projects/defined/index.js" 7COVERED "/home/substack/projects/defined/index.js" 6COVERED "/home/substack/projects/defined/test/whatever.js" 15COVERED "/home/substack/projects/defined/test/whatever.js" 14ok 1 should be equal1..1# tests 1# pass 1# ok

These COVERED and COVERAGE statements are just printed on stdout and they can be fed into the coverify command to generate prettier output:

$ browserify -t coverify test/whatever.js | node | coverifyTAP version 13# whateverok 1 should be equal1..1# tests 1# pass 1# ok# /home/substack/projects/defined/index.js: line 6, column 9-32 console.log('whatever'); ^^^^^^^^^^^^^^^^^^^^^^^^# coverage: 30/31 (96.77 %)

To include code coverage into your project, you can add an entry into the package.json scripts field:

{ "scripts": { "test": "tape test/.js", "coverage": "browserify -t coverify test/.js | node | coverify" }}

There is also a covert package that simplifies the browserify and coverify setup:

{ "scripts": { "test": "tape test/.js", "coverage": "covert test/.js" }}

To install coverify or covert as a devDependency, run npm install -D coverify or npm install -D covert.