Not creating JSON report - missing coverage variable?

[bcwatson22]

Hi, I've been trying to use your plugin but am having some difficulty with it.

I'm using gulp-mocha-phantomjs to run the tests and gulp-istanbul to instrument the code, setting coverageVariable: '__coverage__' in the options object - which appears in the outputted instrumented file. However, when I then try to use mocha-phantomjs-istanbul as the Phantom hook in the subsequent task it never creates the coverage.json file.

I've been consoling from the node_modules/mocha-phantomjs-istanbul/index.js and it doesn't seem to be able to find the coverage variable, getting to line 14 if (!coverage) {...} and then returning. My gulp tasks are as follows:

var mochaPhantomJS = require('gulp-mocha-phantomjs'),
    istanbul = require('gulp-istanbul');

gulp.task('test-instrument', function () {
    return gulp.src('./source/assets/js/modules/*.js')
        .pipe(istanbul({
            coverageVariable: '__coverage__',
            coverageReporter: {
                 includeAllSources: true
            }
        }))
        .pipe(gulp.dest('./source/assets/js/instrumented'));
});

gulp.task('test-dev', ['test-instrument'], function () {
    return gulp.src('./test/unit/template.html', {read: false})
        .pipe(mochaPhantomJS({
            phantomjs: {
                hooks: 'mocha-phantomjs-istanbul',
                coverageFile: './test/unit/coverage.json'
            },
            reporter: 'spec'
        }))
        .on('error', stack.mochaSilentFail);
});

Am I doing anything wrong? Or if it's an issue with how the code is being instrumented please can you suggest an alternative way of doing this?

Really appreciate your help, cheers!