Formatting in tests

Since we added the .clang-format file, some of the tests that were formatted look a bit off now. For example, the brace initialized std::vector here are no longer formatted as a 4x6 matrix.

One possible solution is to check out the clang-format settings and figure out if there's a setting that works for our test code.

https://clang.llvm.org/docs/ClangFormatStyleOptions.html

Another one would be to put // clang-format [off | on] around such sections we do not want to have formatted.