When you create database test in a MsTest project, usually it configure an initialization method that deploy the database schema before test runs.
If something went wrong during this phase you probably will end with this not so much useful error message: Failed to deploy database project …
And if you look at test result you have no more clue on what is actually failing.
To see actual error you need to look at the Run details
Now you can see much more useful information on what is really gone wrong.
From this log you can verify that some post build action went wrong. So do not forget to always take a look at run detail to have detail on what is the reason of failure of the test.