Integration Testing

Integration testing exercises two or more parts of an application at once, including the interactions between the parts, to determine if they function as intended. This type of testing identifies defects in the interfaces between disparate parts of a codebase as they invoke each other and pass data between themselves.

How is integration testing different from unit testing?

While unit testing is used to find bugs in individual functions, integration testing tests the system as a whole. These two approaches should be used together, instead of doing just one approach over the other. When a system is comprehensively unit tested, it makes integration testing far easier because many of the bugs in the individual components will have already been found and fixed.

As a codebase scales up, both unit and integration testing allow developers to quickly identify breaking changes in their code. Many times these breaking changes are unintended and wouldn't be known about until later in the development cycle, potentially when an end user discovers the issue while using the software. Automated unit and integration tests greatly increase the likelihood that bugs will be found as soon as possible during development so they can be addressed immediately.

Integration testing resources

What else do you want to learn about testing?

How do I create unit tests?

Can I automate testing and deployments for my app?

What code metrics should I be aware of?

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