How to use the mockery.deregisterMock function in mockery

it('should attempt to download the build tools', (done) => {
      const nuggetMock = function (url, options, cb) {
        url.should.equal(constants.buildToolsUrl)
        options.should.be.ok
        options.target.should.be.ok
        options.dir.should.be.ok

        cb()
      }

      mockery.registerMock('nugget', nuggetMock)
      require('../../lib/download')().should.be.fulfilled.and.notify(done)
      mockery.deregisterMock('nugget')
    })
  })

afterEach(function(done) {
		mockery.deregisterMock('mongoose');
		mockery.deregisterMock('../utils/event');
		done();
	});

afterEach((done) => {
        mockery.deregisterMock('mongoose');
        mockery.deregisterMock('eventemitter2');
        mockery.deregisterMock('./event');
        mockery.deregisterMock('../utils/event');
        done();
    });

afterEach((done) => {
        mockery.deregisterMock('mongoose');
        mockery.deregisterMock('eventemitter2');
        mockery.deregisterMock('../utils/event');
        mockery.deregisterMock('./event');
        done();
    });

it('should call load configuration with parametered config path', function() {
            var fakeConfigPath = 'fakeConfig.conf';
            mockery.registerMock('optimist', { argv: { config: fakeConfigPath } });
            
            configurationManagerMock.loadConfiguration.reset();
            mockery.resetCache();
            
            createMain();
            
            main.start();
            
            expect(configurationManagerMock.loadConfiguration).to.have.been.calledWith(fakeConfigPath);
            
            mockery.deregisterMock('optimist');
        });