node-harmony-basic-boilerplate/test/util/jasmine-generator-patch.js

An absolutely minimal boilerplate for making node harmony (ES6) apps with suspend, gulp, and jasmine.

var suspend = require('suspend'),
isGeneratorFn = require('is-generator').fn;

/**
* Adds very crude generator support to jasmine's 'it', 'fit', 'beforeEach',
* and 'afterEach' methods.
* Achieved with the help of a bit of bodgery to jasmine's 'env'.
*
* Once this has been 'require'd in, the above jasmine methods will all accept
* generator functions, and will wait for the entire generator to run (similar
* to calling with 'yield*') before the test/step is considered completed.
*/
module.exports = (function() {
    var isIt = /it$/,
    funcs = ['fit', 'it', 'beforeEach', 'afterEach'];

    var env = jasmine.getEnv();
    funcs.forEach(name => {
        var fnArg = isIt.test(name) ? 1 : 0,
        shouldArg = !!fnArg ? 0 : undefined,
        original;

        original = env[name];
        env[name] = wrapForGen(original, env, fnArg, shouldArg);
    });

    function wrapForGen(method, env, fnArg, shouldArg) {
        return function() {
            var fn = arguments[fnArg],
            should = shouldArg === undefined ? '' : arguments[shouldArg],
            outArgs = [];
            
            if(isGeneratorFn(fn)) {
                outArgs[fnArg] = function(done) {
                    suspend.run(fn, function(err) {
                        if(err) {
                            if(err.stack) {
                                // Jasmine doesn't seem to display the stack - so put
                                // it in the message to be reported with the result
                                err.message = err.stack;
                            }
                            // Grab the current top-level Suite and report the
                            // exception directly to it (which relays it to
                            // children suites/specs)
                            jasmine.getEnv().topSuite().onException(err);
                        }
                        done();
                    });
                };

                should && (outArgs[shouldArg] = should);
                return method.apply(env, outArgs);
            } else {
                return method.apply(env, arguments);
            }
        };
    }
})();