Both Safari and Chrome have the ability to “spoof” the browser and emulate different devices. In Safari you must turn on developer tools in preferences and then you can select Develop Menu >Enter Responsive Design Mode.
Google’s has also cleaned up their interface. To test mobile you go to developer tools (buried in the hamburg menu on the right-hand side of the screen under “more tools”) and then click on the little mobile icon and your screen will display this way:
For me Safari is *usually* good enough. Android is fragmented enough and it’s screen sizes are close enough to iDevices that once we’ve tested on a couple of iDevices we usually ship it and handle any issues that get reported post-launch.