Investigate better testing solution

[svenstaro]

• https://www.reddit.com/r/rust/comments/5jbezo/testing_frameworks/
• http://neikos.me/Using_Stainless_with_Rocket.html
• https://github.com/kriomant/mockers/blob/master/doc/guide.md
• https://github.com/SimonKagstrom/kcov
• https://docs.rs/mock_me/0.2.2/mock_me/
• https://github.com/cksac/fake-rs
• https://github.com/tikotzky/faker-rs
• https://github.com/kennytm/cargo-kcov
• https://github.com/roblabla/cargo-travis
• http://sunjay.ca/2016/07/25/rust-code-coverage