Test uncaught exception with mocha tests runner

mocha-uncaught-exception.js

var should = require('should');

describe('uncaught exception', function() {
  describe('with interception', function() {
    var listeners;

    beforeEach(function() {
      listeners = process.listeners('uncaughtException');

      process.removeAllListeners('uncaughtException');
    });

    afterEach(function() {
      listeners.forEach(function(listener) {
        process.on('uncaughtException', listener);
      });
    });

    it('should be handled', function(done) {
      process.once('uncaughtException', function(err) {
        should(err.message).eql('Unhandled');

        done();
      });

      setImmediate(function() {
        throw new Error('Unhandled');
      });
    });
  });

  describe('without interception', function() {
    // Would produce duplicated tests
    it('should not be handled', function(done) {
      process.once('uncaughtException', function(err) {
        should(err.message).eql('Unhandled');

        done();
      });

      setImmediate(function() {
        throw new Error('Unhandled');
      });
    });
  });
});