This course is a TDD best practical tutorial, i will tutorial the TDD concepts at the second section by high level and details explain development work flow. TDD provides several benefits:

1. It can enable faster innovation and continuous delivery because the code is robust.

2. It makes your code flexible and extensible. The code can be refactored or moved with minimal risk of breaking code.

3. The tests themselves were tested. A key characteristic of a test is that it can fail, and the development team verifies that each new test fails.

4. The code that is designed easy to test.

5. The requirements are implemented with little to no wasted effort because only the function that will be implement.

At the third and fourth section we implement the arithmatic expression by three version

1. string textual split

2. regular expression

3. Stack with infix to postfix and then evaluate

finally we will implement the result of: (13 + 4) * 2 + 3^2 = ?

Test Driven Development (TDD) is software development approach in which test cases are developed to specify and validate what the code will do.

Test-Driven Development starts with designing and developing tests for every small functionality of an application.

TDD rooted in extreme programming(XP), and is one of the best pracitice of Agile methodology.