V-Model

Updated 06 Sep 2026

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What it is
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  a plan-driven process model (Verification & Validation Model) that pairs each development phase with a corresponding testing phase, forming a V-shape
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Pairings
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  requirements analysis -> acceptance testing
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  system design -> system testing
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  high-level design -> integration testing
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  low-level design -> unit testing
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  implementation sits at the bottom of the V, connecting the two sides
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Strengths / weaknesses
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  testing is planned from the very start, improving quality and reducing failure risk; suited to safety-critical projects (e.g. medical software)
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  inflexible to changing requirements; testing-heavy, so costly
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Related
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  Waterfall Model
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  Testing Levels
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Cards
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  What does the V-Model pair each development phase with?
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    a corresponding testing phase — e.g. requirements analysis <-> acceptance testing, system design <-> system testing

Linked references 2