When I first started writing unit tests, I followed the common convention in C# for method naming:
Later, I adopted the convention of separating words with underscores:
At some point I figured the approach above makes the name of the method look like the title of an article. I then decided to go with the same approach, but making everything lower case:
In some cases, I may use uppercase if I want to draw attention to something in particular:
I like when the code is calm to look at, and it draws my attention to things as appropriate.