The testing pyramid is a simple way to visualize the different types of tests and their impact.
At the base of the testing pyramid are unit tests.
These are the fastest and least expensive tests to run, and they are located directly in the code.
In the middle of the testing pyramid are integration tests.
They verify that all developments from different parts work correctly together.
These tests take longer to run, so there are fewer of them.
At the top of the testing pyramid are manual or functional tests.
These are the most expensive and slowest tests. They are performed at the final stage to ensure everything works correctly.
The testing pyramid helps understand the different types of tests and why unit tests are preferred over manual tests.
The earlier a bug is detected, the more time and money are saved in fixing it.