Run tap/tape tests from within Grunt and throw errors appropriately.

Gruntfile.js

grunt.registerMultiTask('tape', 'Run tap/tape tests from within grunt.', function () {
  var done = this.async();
  var faucet = require('faucet');
  var tapParser = require('tap-parser');

  var parser = tapParser(function (results) {
    if (results.fail > 0) {
      grunt.fail.warn(results.fail + ' test(s) have failed');
    } else {
      done();
    }
  });

  var runner = grunt.util.spawn({
    args: this.filesSrc,
    cmd: require.resolve('tape/bin/tape')
  }, function() {});
  runner.stderr.pipe(process.stderr, { end: false });
  runner.stdout.pipe(parser);
  runner.stdout.pipe(faucet()).pipe(process.stdout);
});