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Documents the project testing philosophy: all resolver tests must use live DNS queries. Mocking the DNS client layer is not permitted. Includes rationale and anti-patterns to avoid.
35 lines
1.3 KiB
Markdown
35 lines
1.3 KiB
Markdown
# Testing Policy
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## DNS Resolution Tests
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All resolver tests **MUST** use live queries against real DNS servers.
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No mocking of the DNS client layer is permitted.
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### Rationale
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The resolver performs iterative resolution from root nameservers through
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the full delegation chain. Mocked responses cannot faithfully represent
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the variety of real-world DNS behavior (truncation, referrals, glue
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records, DNSSEC, varied response times, EDNS, etc.). Testing against
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real servers ensures the resolver works correctly in production.
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### Constraints
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- Tests hit real DNS infrastructure and require network access
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- Test duration depends on network conditions; timeout tuning keeps
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the suite within the 30-second target
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- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms)
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plus processing margin
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- Root server fan-out is limited to reduce parallel query load
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- Flaky failures from transient network issues are acceptable and
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should be investigated as potential resolver bugs, not papered over
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with mocks or skip flags
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### What NOT to do
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- **Do not mock `DNSClient`** for resolver tests (the mock constructor
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exists for unit-testing other packages that consume the resolver)
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- **Do not add `-short` flags** to skip slow tests
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- **Do not increase `-timeout`** to hide hanging queries
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- **Do not modify linter configuration** to suppress findings
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