Fix flaky runtime-metrics tests with condition-based collection wait (#7231)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: bm1549

tests/test_config_consistency.py

@@ -662,6 +662,7 @@ class Test_Config_RuntimeMetrics_Enabled:
 
     def setup_main(self):
         self.req = weblog.get("/")
+        wait_for_runtime_metrics()
 
     def test_main(self):
         assert self.req.status_code == 200
@@ -696,6 +697,7 @@ class Test_Config_RuntimeMetrics_Enabled_WithRuntimeId:
 
     def setup_main(self):
         self.req = weblog.get("/")
+        wait_for_runtime_metrics()
 
     def test_main(self):
         assert self.req.status_code == 200
@@ -746,6 +748,18 @@ def get_runtime_metrics():
     return runtime_metrics_gauges, runtime_metrics_sketches
 
 
+RUNTIME_METRICS_WAIT_TIMEOUT = 60
+
+
+def wait_for_runtime_metrics() -> None:
+    # Runtime metrics are emitted on an interval, so wait (while the weblog is still up) until at least one
+    # reaches the agent instead of relying on the fixed collection window, which is racy.
+    interfaces.agent.wait_for(
+        lambda _: any(len(metrics) > 0 for metrics in get_runtime_metrics()),
+        timeout=RUNTIME_METRICS_WAIT_TIMEOUT,
+    )
+
+
 def parse_log_injection_message(log_message: str) -> dict:
     if context.library == "ruby":
         # TODO: Update ruby weblog app to support structured logs

tests/test_otlp_runtime_metrics.py

@@ -251,13 +251,30 @@ def get_runtime_metrics_by_name() -> dict[str, list[dict[str, str]]]:
     return result
 
 
+RUNTIME_METRICS_WAIT_TIMEOUT = 60
+
+
+def wait_for_runtime_metrics(library: str) -> None:
+    # OTLP metrics are exported on an interval, so wait (while the weblog is still up) until every expected
+    # metric for this library reaches the agent instead of relying on the fixed collection window.
+    expected = EXPECTED_METRICS.get(library)
+    if not expected:
+        return
+
+    interfaces.agent.wait_for(
+        lambda _: expected.keys() <= get_runtime_metrics_by_name().keys(),
+        timeout=RUNTIME_METRICS_WAIT_TIMEOUT,
+    )
+
+
 @scenarios.otlp_runtime_metrics
 @features.runtime_metrics
 class Test_OtlpRuntimeMetrics:
     """Verify runtime metrics are sent via OTLP with OTel names, not DD-proprietary names."""
 
     def setup_otel_metrics_are_present_and_attributed(self) -> None:
         self.req = weblog.get("/")
+        wait_for_runtime_metrics(context.library.name)
 
     def test_otel_metrics_are_present_and_attributed(self) -> None:
         assert self.req.status_code == 200