fix: Replace arbitrary sleeps with active server readiness checks in tests #1527
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…tests Eliminates race conditions in HTTP server tests by replacing fixed sleep delays with deterministic server readiness polling. This makes tests more reliable and often faster by eliminating unnecessary waits. Changes: - Created shared wait_for_server() helper in tests/test_helpers.py - Fixed flaky time.sleep(1) in test_streamable_http_security.py - Replaced duplicate wait_for_server() in test_sse_security.py with shared helper - Improved consistency by updating all HTTP server test fixtures in: - tests/shared/test_ws.py - tests/shared/test_sse.py - tests/shared/test_streamable_http.py The wait_for_server() helper: - Actively polls the server port by attempting TCP connections - Returns immediately when the server accepts connections - Uses 0.01-second intervals between attempts - Has a 5-second timeout that raises TimeoutError on true failures - Makes tests deterministic instead of probabilistic 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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This change completes the work started in PR #1527 by fixing the remaining test fixtures that were still using manual socket polling loops to wait for server startup. ## Changes Fixed 4 test fixtures that were missed in the previous PR: - tests/server/fastmcp/test_integration.py: server_transport fixture - tests/client/test_notification_response.py: non_sdk_server fixture - tests/client/test_http_unicode.py: running_unicode_server fixture - tests/shared/test_sse.py: mounted_server and context_server fixtures All now use the centralized wait_for_server() helper which: - Actively polls for TCP connection readiness - Returns immediately when server is ready - Has clear timeout behavior (5s default) - Eliminates race conditions from arbitrary sleeps ## Impact - Removes 49 lines of duplicate manual polling code - Makes tests more deterministic and reliable - Reduces wasted time from fixed delays (tests return as soon as ready) - Follows the patterns documented in FLAKY_TESTS.md
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Fixes flaky test failures by replacing arbitrary sleep delays with deterministic server readiness polling across all HTTP server tests.
Motivation and Context
Multiple test files were using either fixed
time.sleep()delays or manual polling loops with inconsistent implementations to wait for servers to start. This approach was problematic because:This PR follows the same approach as #1526, which fixed similar issues in
test_sse_security.py.How Has This Been Tested?
Verified the fix: Ran all affected test suites successfully:
test_streamable_http_security.py: 7 passedtest_sse_security.py: 8 passedtest_ws.py: 4 passedtest_sse.py: 16 passed, 1 skippedtest_streamable_http.py: 33 passedConsistency check: All test files now use the same centralized
wait_for_server()helperPerformance: Tests complete in similar or faster time since they don't wait unnecessarily
Breaking Changes
None. This is purely an internal test improvement with no impact on the public API or user code.
Types of changes
Checklist
Additional context
The new
wait_for_server()helper intests/test_helpers.py:TimeoutErroron true failuresThis follows the principles outlined in the repository's approach to avoiding flaky tests by using active condition checking rather than arbitrary sleeps.