Code Coverage reported as 0% after upgrading from 3.0.1 to 4.0.1

[ek9]

I am experiencing a weird issue where upgrading gulp-mocha from 3.0.1 to 4.0.1 causes code coverage to no longer work. The tests run as before, but istanbul is no longer able to pick things up and it reports 0% code coverage.

This affects this PR https://github.com/ek9/generator-license-cc/pull/25/files

Test coverage before update ( https://travis-ci.org/ek9/generator-license-cc/jobs/195271001 ):

  21 passing (1s)

-----------|----------|----------|----------|----------|----------------|

File       |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |

-----------|----------|----------|----------|----------|----------------|

 app/      |      100 |     93.1 |      100 |      100 |                |

  index.js |      100 |     93.1 |      100 |      100 |                |

-----------|----------|----------|----------|----------|----------------|

All files  |      100 |     93.1 |      100 |      100 |                |

-----------|----------|----------|----------|----------|----------------|

Test coverage after update ( https://travis-ci.org/ek9/generator-license-cc/jobs/205308602 ):

  21 passing (950ms)

-----------|----------|----------|----------|----------|----------------|

File       |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |

-----------|----------|----------|----------|----------|----------------|

 app/      |        0 |        0 |        0 |        0 |                |

  index.js |        0 |        0 |        0 |        0 |... 294,295,297 |

-----------|----------|----------|----------|----------|----------------|

All files  |        0 |        0 |        0 |        0 |                |

-----------|----------|----------|----------|----------|----------------|

gulpfile.js

'use strict';
var path = require('path');
var gulp = require('gulp');
var eslint = require('gulp-eslint');
var excludeGitignore = require('gulp-exclude-gitignore');
var mocha = require('gulp-mocha');
var istanbul = require('gulp-istanbul');
var nsp = require('gulp-nsp');
var plumber = require('gulp-plumber');
var coveralls = require('gulp-coveralls');

// ... some parts omitted ...

gulp.task('pre-test', function () {
  return gulp.src('app/*.js')
    .pipe(excludeGitignore())
    .pipe(istanbul({
      includeUntested: true
    }))
    .pipe(istanbul.hookRequire());
});

gulp.task('test', ['pre-test'], function (cb) {
  var mochaErr;

  gulp.src('test/**/*.js')
    .pipe(plumber())
    .pipe(mocha({reporter: 'spec'}))
    .on('error', function (err) {
      mochaErr = err;
    })
    .pipe(istanbul.writeReports())
    .on('end', function () {
      cb(mochaErr);
    });
});

For full source you can check the PR or repository ek9/generator-license-cc#25 (comment)

[ek9]

I tried to have a look on what is affecting this, but since it was a major rewrite, I don't think I can pin-down where the problem is without further assistance.

[agracio]

Just tested it in my project and coverage is also 0% on 4.0.1

gulpfile.js snippet:

gulp.task('pre-coverage',  function () {
        return gulp.src(paths.out + '/src/progress.js')
            .pipe(istanbul({includeUntested: true}))
            .pipe(istanbul.hookRequire());
});

gulp.task('istanbul', ['pre-coverage'], function () {
        return gulp.src(paths.test, {read: false})
            .pipe(mocha({reporter: 'spec'}))
            .pipe(istanbul.writeReports({
                dir: paths.coverage,
                reporters: [ 'json' ],
                reportOpts: { dir: paths.coverage}
            }));
});

[skarfacegc]

I think the issue is that gulp-mocha is now acting on files rather than on the stream from the istanbul pipeline. I think this was the tradeoff for making compilers work. :/

You can probably use instanbul to instrument your src into a tmp directory and run the tests against those.

[sindresorhus]

It always acted on the file paths, not the files object. Nothing has changed in that regard.

[chris-jones-pixitmedia]

I'm experiencing the same issue after updating

[zozzz]

The problem is that spawning mocha instead use of mocha api. The gulp-istanbul plugin patch require function to import patched sources. If spawn mocha process then the patched require function is now longer available in the new process.

I think a good solution is make a option that switch between spawn and api.