Core htmx API test

• ajax api with no context works4ms ‣

  // request would replace body so prevent ths with 204 response
  var status
  var handler = htmx.on('htmx:beforeSwap', function(event) {
    status = event.detail.xhr.status
  })
  this.server.respondWith('GET', '/test', function(xhr) {
    xhr.respond(204, {}, 'foo!')
  })
  var div = make('<div></div>')
  htmx.ajax('GET', '/test')
  this.server.respond()
  div.innerHTML.should.equal('')
  status.should.equal(204)
  htmx.off('htmx:beforeSwap', handler)