Update README.md

Author: shubhamd99

README.md

@@ -1,9 +1,31 @@
 ### Simple React Native Typescript with Jest Testing Library
 
+##### What is a Test?
+* Code you write to verify the behavior of your application.
+* Tests are a specifications for hwo our code should work.
+* Verify that engineers are following best practices and conventions for your team.
+* We write tests because it allows us to ship quality code faster.
+
+##### Types of Tests?
+* End-to-End: Spin up your app and simulate user behaviour. Kind of like a robot performing a task in your app.
+* Integration: Verify that multiple units work together.
+* Unit: Verify the functionality of a single function/component.
+* Static: Catch typos and errors while riting code.
+
+##### A Jest Test
+```
+const expected = true;
+const actual = false;
+
+test("it works", () => {
+    expect(actual).toBe(expected);
+});
+```
+
 * npx react-native init MyApp --template react-native-template-typescript
 
 * npm install --save @testing-library/react-native @testing-library/jest-native
 
 * Official Docs - https://testing-library.com/docs/
 
-* npm run test --watch
+* npm run test --watch