As a software engineering paradigm, both behavior driven development vs. Test-driven development are kinds of Agile Development Methodology that encourage collaboration between development teams, testing teams, non-technical and business participants.
For most of the people, terms like Unit tests, test driven development and behavior driven development were used interchangeably, but while TDD focusses on the developer’s opinion on how parts of the software should work, BDD, on the other hand, focuses on the users’ opinion on how they want their applications to behave.
Developers perform unit tests on their codes/single unit of code that is usually a function in an object or a module.
There can be several unit tests on various parts of the program.
Only once the program passes all the unit tests, it is then escalated to the test team for various other tests that include regression tests, integration tests, system tests, smoke tests, and user acceptance tests.
It helps enhance business value by defining the problem and suggesting solutions simultaneously.