TDD

TDD (Test Driven Development) is an approach for software development where Test is written before starting the development.

Steps are

Suppose you are planning to write a function for adding two numbers. Than

1. Write the Test first to test that function that is in your mind but not exist yet.
2. Now write the function for adding to two number.
3. Now run the test that you have written already.

Repeat the these for every single function you are planing to write.