Definition - What does Bottom-Up Testing mean?
IT professionals refer to design assemblies, or groups of code modules that are evaluated for overall functioning, in integrated testing environments.
Techopedia explains Bottom-Up Testing
Bottom-up testing is the opposite of top-down testing, where the top integrated elements are tested first. Experts explain that while bottom-up testing can be useful in producing a smaller, independent test basis, it doesn't provide the same kind of skeletal program demonstration design that top-down testing does. With bottom-up testing, developers build up to that scale where the program mainly coincides with the user interface. Some people see this as a kind of backward testing, but each individual developer team must decide for reasons of purpose and practicality which type of software testing suits the project better.