If enabled on your account you will be able to watch a video recording of a candidate's test. This will show you all of the keystrokes made and where they have clicked on the page.
It's possible to go through it section by section and analyze the test in a lot of detail. To access the recording, click on the candidate, and then the test invite. You will then see a button that says 'Show screen recording'.
If you have a test that lasts a considerable amount of time and the candidate was to leave and come back, this will have no effect on the recording as the system will on record when there is activity.
Please note, that the session recording is available for 30 days only.

With session recording, you can not only follow the actions performed by your candidate while in the test but also check some detailed information about the test.
To see the details, please click on the 'eye' icon. You will get the details about the Session, Device, and Location as shown on the screenshot below.

As an additional security feature, if your candidate posted the link to the test somewhere on the internet, you will be able to see it in the 'Referrer' field.