Sensor family 02
Behavioral
“Does it do what we expect?”
What belongs here
These sensors run the system on inputs a human chose and compare what happened against an answer a human supplied. The oracle is external and specific: it is exactly as good as the example, and it says nothing about the cases nobody wrote down.
Contested placements
Synthetic Monitoring runs the same chosen-input check against production, which makes it as much a runtime sensor as a behavioural one. It is grouped here because its oracle is a scripted expectation rather than an observation of real traffic.
Where its signals arrive
- Behavioral tests — Test stage. Does it do what we expect for given inputs?
- Integration tests — Test stage. Does it work connected to its real dependencies?
The atlas places every family on the same lifecycle grid; the framework defines the six dimensions each entry below is characterized along.
Entries (6)
Contract Tests
Does service A continue satisfying the assumptions of service B? Contract tests are a sensor of boundary assumptions — the implicit agreements between independent components about what the interface…
Example-Based Tests
Given X, expect Y. The fundamental behavioral sensor. Fundamentally different from coverage: coverage says “this code executed.” A behavioral assertion says “this code produced the right result.”…
Integration Tests
Does the thing work when connected to its actual dependencies? Catches failures that unit tests structurally cannot see — connection failures, serialization mismatches, timeout behavior.
Smoke Tests
The cheapest behavioral check against a live deployment: hit /health, create one record, read it back, delete it. If any step fails, roll back.
Snapshot Tests
Did observable output change? Not “is it correct” but “did it change” — a sensor for detecting unintended drift in externally observable artifacts.
Synthetic Monitoring
Scripted user flows run against the production system around the clock: log in, search, add to cart, check out.
Adjacent families
- Previous: Structural — Is this artifact internally coherent?
- Next: Test Effectiveness — Do our tests actually detect failures?
- All of them: the complete catalog (this family is also anchored there at /catalog/#behavioral).