Component tests with React testing library

[fess986]

• [x] #217
• [x] Component logo tests
• [x] Component 404 tests
• [x] Component sign-in tests
• [x] Component SmallFilmCard tests
• [x] Component Genres tests
• [x] Component MyListButton tests
• [x] Component ShowMoreButton tests
• [x] Component AddReviewButton tests
• [x] Component FilmList tests
• [ ] Component UserBlock tests

[fess986]

Component 404 test resolved by cb9da14

[fess986]

Component logo test resolved by 5824672

[fess986]

Component sign-in test resolved by b083b13

[fess986]

Component SmallFilmCard tests resolved by 5d58f59

[fess986]

Component Genres tests resolved by bf754a9

[fess986]

Component MyListButton tests resolved by 602f7b0

[fess986]

Component ShowMoreButton tests resolved by 42c8d99

[fess986]

Component AddReviewButton tests resolved by ba63b12

[fess986]

Component FilmList tests resolved by cce21af

[fess986]

Component UserBlock tests resolved by 794eb19