Methodologies: Test Driven Development

https://martinfowler.com/bliki/TestDrivenDevelopment.html

Quoting:
"Test-Driven Development (TDD) is a technique for building software that guides software development by writing tests. It was developed by Kent Beck in the late 1990's as part of Extreme Programming. In essence you follow three simple steps repeatedly:

Write a test for the next bit of functionality you want to add.Write the functional code until the test passes.Refactor both new and old code to make it well structured.

You continue cycling through these three steps, one test at a time, building up the functionality of the system. "

The book (by Kent Beck):
https://www.amazon.com/gp/product/0321146530?ie=UTF8

RESOURCE: On Software Development Methodologies

The non-exaustive-use-with-care list of resources on software development methodologies includes some additional information on the waterfall - agile/scrum "recipes" - some of which include variants and/or predecessors of it:

• https://en.wikipedia.org/wiki/Software_development_process - several methodologies listed including FDD, TDD, etc.
• https://en.wikipedia.org/wiki/Software_development_process#Spiral_development - focus on iterative deliveries and risk management as well as planning as explicit parts of the methodology
• https://en.wikipedia.org/wiki/Extreme_programming - unit testing, pair programming, involve the end-customer, stand-up meetings
• https://en.wikipedia.org/wiki/Software_development_process#Agile_development
• https://en.wikipedia.org/wiki/Scrum_(software_development)