Getting compile error about missing == operator

[mgerhardy]

error C2679: binary '==': no operator found which takes a right-hand operand of type 'const std::string_view' (or there is no acceptable conversion)

• https://ci.appveyor.com/project/mgerhardy/engine/build/0.1-198#L3843
• https://github.com/mgerhardy/engine/blob/master/src/modules/core/tests/StringTest.cpp