Chapter 2 – Testing Throughout the SDLC
Top-Down Integration – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
An incremental approach to integration testing in which the highest level components are tested first, and lower level components are simulated by stubs.
In simple words
Integrate from the top downward, using stubs for anything not built yet.
Exam tip
Requires stubs; contrast with bottom-up which needs drivers.
Related terms
- Integration TestingAfter units work alone, you plug them together and check the seams — API calls, data hand-offs, contracts.
- Bottom-Up IntegrationIntegrate from the bottom upward, using drivers to call low-level modules.
- StubFake code you drop in for a not-yet-built dependency so your module can be tested.
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