The best practice is to write the test by knowing all the scenarios.
Usually this is the practice I have seen successful in all the big projects
- unit test for each function
- Functional Integration test to test the building blocks and functions together (for example rest API with business layer and database
- BDD Behavior driven development where you write automated test to test your business scenarios by initializing the seed data in the test systems
- Performance testing
If you have freelancer who charge per hour or if you have consultants which are expensive - they will write too many test and there code will be so complex in the end that when you want to hire permanent employees or other freelancers they will say "I would like to rewrite it"
The developers now a days like to do clean coding and for simple things they discuss too much even for a program of 2 + 2. there will be endless discussions and in some companies (diverse or multi culture) developers are always under mining each other with what they like and don't like
Usually this is the practice I have seen successful in all the big projects
- unit test for each function
- Functional Integration test to test the building blocks and functions together (for example rest API with business layer and database
- BDD Behavior driven development where you write automated test to test your business scenarios by initializing the seed data in the test systems
- Performance testing
If you have freelancer who charge per hour or if you have consultants which are expensive - they will write too many test and there code will be so complex in the end that when you want to hire permanent employees or other freelancers they will say "I would like to rewrite it"
The developers now a days like to do clean coding and for simple things they discuss too much even for a program of 2 + 2. there will be endless discussions and in some companies (diverse or multi culture) developers are always under mining each other with what they like and don't like