I'm just going to leave this here:

More background with the test pyramid (links are definitely not endorsements in this case):

• http://martinfowler.com/bliki/TestPyramid.html
• https://testing.googleblog.com/2015/04/just-say-no-to-more-end-to-end-tests.html
• https://www.mountaingoatsoftware.com/blog/the-forgotten-layer-of-the-test-automation-pyramid