Billy Reilly questions

Billy Reilly answers

• Jest check if an elements attribute exists
• What is the actual use of toContain() in expect?
• Enforcing newlines separating code blocks in eslint
• jest.spyOn method that return a Promise
• MomentJS: how to parse dates in MM/DD/YYYY & DD/MM/YYYY
• Mock fs function with jest
• React testing state of component with Jest and Enzyme