public function testSetUserProperties()
{
$userProps = ['dob' => 'tomorrow', 'gender' => 'f'];
$event = new Event();
$event->setUserProperties($userProps);
$this->assertSame(['user_properties' => $userProps], $event->toArray(), 'Should set user properties in user_properties');
$userProps2 = ['dob' => 'yesterday', 'name' => 'Baby'];
$expected = ['dob' => 'yesterday', 'gender' => 'f', 'name' => 'Baby'];
$event->setUserProperties($userProps2);
$this->assertSame(['user_properties' => $expected], $event->toArray(), 'Second call to setUserProperties should update properties, not remove existing');
}
