Integration Testing Kubernetes Network Policies
The cluster was dark until the test lit it up. Pods spoke, some stayed silent, and the network rules either held firm or fell apart. Integration testing for Kubernetes network policies is the only way to know which will happen before production carries the cost.
Kubernetes Network Policies control pod-to-pod and pod-to-service communication at the IP level. They define what traffic is allowed and what is blocked across namespaces. Without testing, a single misconfigured policy can open attack surfaces or cut off critical paths. Configuration alone is not proof; execution is.
Integration testing goes beyond unit or policy linting. It runs your workloads in a real cluster or a close staging replica. The goal is to simulate how Pods, Services, and Namespaces behave when network rules apply. This reveals incorrect selectors, default-deny gaps, and policy overlaps before they reach users.
A solid process starts with defining clear scenarios:
- Pod allowed to talk to another Pod within the same namespace
- Cross-namespace denial enforced correctly
- External ingress rules tested from known IP ranges
- Egress restrictions applied without breaking upstream calls
Use ephemeral namespaces and controlled fixtures to keep tests clean. Automate creation and teardown through CI pipelines. Apply policies as YAML, deploy test Pods, then hit them with network requests from allowed and disallowed sources. Capture logs and metrics — a denied connection should fail fast; an allowed one should pass without delay.
Cluster networking varies with the CNI plugin. Calico, Cilium, and Weave Net all follow Network Policy specs but handle implementation details differently. Integration testing makes those differences visible. You learn exactly how the CNI enforces rules, how fast, and if it matches your security model.
Run tests with real traffic rather than mocks. Use tools like kubectl exec with curl or netcat to prove connectivity or isolation. For high coverage, script multiple test paths and verify them in parallel. Integrate this into continuous delivery so every deployment validates network governance along with application logic.
Done right, integration testing for Kubernetes network policies gives you confidence: services connect where they should, and isolation is airtight everywhere else. That is the difference between “it should work” and knowing it works.
See it live with hoop.dev and spin up a full integration test environment in minutes — your policies, your clusters, proven in action.