The easiest way to install Qt on Windows is via the Online installer. Note that while this by far the easiest way to install that I've been able to find, it does require the creation of a Qt account and using those credentials within the Online installer. The only other method I've been able to find for getting Qt without using the Online installer, is to download the source and compile it yourself.
Assuming the Online installer is used:
If opting not create a Qt account and compiling the source manually, please follow their instructions.
Google Test is used for Unit and any other automated tests within the project. In order to compile and run them, Google Test must be separately downloaded and installed. Version 1.13.0 is used at present, however it is highly likely that newer versions will work as well.
And done! Once the project is loaded in Qt Creator it will use the environment variable to determine where Google Test is installed to and perform the rest of the necessary work.