Testing Framework & Continuous Execution · 40 min · pytest · Hypothesis · mutmut

The Verification Pyramid for AI Code

Unit every commit. Property every commit. Mutation nightly. Security every PR. Formal at release.

Hiring signal: Engineers who can design a verification pyramid for AI code demonstrate testing architecture expertise.

What you will learn

Design the verification pyramid for AI code with 6 layers
Determine what to run when: commit, PR, nightly, release
Apply cost vs confidence tradeoffs for each verification layer
Map all tools from Phases 1-7 to pyramid layers

The Problem

You have 13+ quality gates from Phases 1-7. Running all of them on every commit is too slow and too expensive. This lesson covers the verification pyramid -- a layered model that determines what to run when, balancing cost and confidence.

The 6-Layer Verification Pyramid

                    ┌───────────┐
                    │  Formal   │  Release only
                    │  (Z3)     │  Highest confidence, highest cost
                    └───────────┘
                 ┌─────────────────┐
                 │    Security     │  Every PR
                 │ (SAST+SCA+AI)   │  High confidence, medium cost
                 └─────────────────┘
              ┌───────────────────────┐
              │     Integration       │  Every PR
              │  (End-to-end tests)   │  Medium confidence, medium cost
              └───────────────────────┘
           ┌───────────────────────────────┐
           │        Mutation Testing       │  Nightly
           │         (mutmut)              │  High confidence, high cost
           └───────────────────────────────┘
        ┌───────────────────────────────────────┐
        │       Property-Based Testing          │  Every commit
        │         (Hypothesis)                  │  Medium confidence, low cost
        └───────────────────────────────────────┘
     ┌───────────────────────────────────────────────┐
     │              Unit Tests                       │  Every commit
     │            (pytest)                           │  Low confidence, low cost
     └───────────────────────────────────────────────┘

Unlock the full lesson

You've read the first 2 sections. The rest of this lesson covers Layer Details, Build It — plus a hands-on lab, quiz, and project artifact.

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