Choosing an Integration Test Suite Methodology

Just as there are preferred methods for identifying and writing unit tests for our code, there are similar methods for identifying and writing integration tests. As a general rule, integration tests are tests involving real instances of services, components, or other dependencies as opposed to mocks or stubs, which are often found in unit testing.

Methodologies

Several methodologies are considered standard when it comes to integration testing. These include the following:

• Big bang: All components are combined together and tested at the same time.

• Top-down: Top-level units are tested first, then lower-level units are tested (that is, testing an API route and then testing the components that the route relies on).

• Bottom-up: Lower-level units are tested first, then top-level units are tested (that is, testing component interaction before testing an API route that relies on those interactions).

• Sandwich/hybrid: This is an intentional mix of top-down and bottom-up methodologies.