fix(tests): Fix flaky test_cross_trace_query_with_spans_and_logs (#109572)

## Problem
The test was using midnight as a timestamp, which caused timing-related
flakiness depending on when the test ran relative to day boundaries.

## Fix
Updated the failing test and related tests to use non-midnight
timestamps so results are stable regardless of execution time.

Fixes GH-106681

Author: manessaraj

tests/sentry/api/endpoints/test_organization_traces.py

@@ -26,6 +26,11 @@ class OrganizationTracesEndpointTest(BaseSpansTestCase, APITestCase):
     def setUp(self) -> None:
         super().setUp()
         self.login_as(user=self.user)
+        # Shared 10am timestamps in the past to avoid midnight flakiness and future timestamps in CI.
+        self.reference_time_10am = before_now(days=1).replace(
+            hour=10, minute=0, second=0, microsecond=0
+        )
+        self.reference_time_10am_3_days_ago = self.reference_time_10am - timedelta(days=2)
 
     def double_write_segment(
         self,
@@ -92,7 +97,7 @@ def create_mock_traces(self):
         timestamps = []
 
         # move this 3 days into the past to ensure less flakey tests
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=3)
+        now = self.reference_time_10am_3_days_ago
 
         trace_id_1 = uuid4().hex
         timestamps.append(now - timedelta(minutes=10))
@@ -418,7 +423,7 @@ def test_use_first_span_for_name(self) -> None:
         trace_id = uuid4().hex
         span_id = "1" + uuid4().hex[:15]
         parent_span_id = "1" + uuid4().hex[:15]
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0)
+        now = self.reference_time_10am
         ts = now - timedelta(minutes=10)
 
         self.double_write_segment(
@@ -481,7 +486,7 @@ def test_use_root_span_for_name(self) -> None:
         trace_id = uuid4().hex
         span_id_1 = "1" + uuid4().hex[:15]
         span_id_2 = "1" + uuid4().hex[:15]
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0)
+        now = self.reference_time_10am
         ts = now - timedelta(minutes=10)
 
         self.double_write_segment(
@@ -568,7 +573,7 @@ def test_use_pageload_for_name(self) -> None:
         trace_id = uuid4().hex
         span_id = "1" + uuid4().hex[:15]
         parent_span_id = "1" + uuid4().hex[:15]
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0)
+        now = self.reference_time_10am
         ts = now - timedelta(minutes=10)
 
         self.double_write_segment(
@@ -631,7 +636,7 @@ def test_selected_projects(self) -> None:
         trace_id = uuid4().hex
         span_id = "1" + uuid4().hex[:15]
         parent_span_id = "1" + uuid4().hex[:15]
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0)
+        now = self.reference_time_10am
         ts = now - timedelta(minutes=10)
         self.create_project()
 
@@ -695,7 +700,7 @@ def test_case_insensitive_filter(self) -> None:
         trace_id = uuid4().hex
         span_id = "1" + uuid4().hex[:15]
         parent_span_id = "1" + uuid4().hex[:15]
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0)
+        now = self.reference_time_10am
         ts = now - timedelta(minutes=10)
 
         self.double_write_segment(
@@ -756,7 +761,7 @@ def test_case_insensitive_filter(self) -> None:
         ]
 
     def test_use_separate_referrers(self) -> None:
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0)
+        now = self.reference_time_10am
         start = now - timedelta(days=2)
         end = now - timedelta(days=1)
         trace_id = uuid4().hex
@@ -932,9 +937,7 @@ def test_matching_tag(self) -> None:
     def test_environment_filter(self) -> None:
         trace_id = uuid4().hex
         span_id = "1" + uuid4().hex[:15]
-        timestamp = before_now().replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(
-            days=3
-        )
+        timestamp = self.reference_time_10am_3_days_ago
 
         self.double_write_segment(
             project=self.project,
@@ -1159,7 +1162,7 @@ def test_sort_by_timestamp(self) -> None:
 
     def test_span_name_as_name(self) -> None:
         project = self.create_project()
-        now = before_now().replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=3)
+        now = self.reference_time_10am_3_days_ago
         trace_id = uuid4().hex
 
         self.double_write_segment(

tests/snuba/api/endpoints/test_organization_events_timeseries_cross_trace.py

@@ -14,10 +14,13 @@ class OrganizationEventsTimeseriesCrossTraceEndpointTest(OrganizationEventsEndpo
 
     def setUp(self) -> None:
         super().setUp()
-        self.day_ago = before_now(days=1).replace(hour=0, minute=0, second=0, microsecond=0)
+        # Events at 10am (not midnight) to avoid flakiness; query window at midnight so interval=1d yields exactly 2 buckets.
+        self.day_ago = before_now(days=1).replace(hour=10, minute=0, second=0, microsecond=0)
         self.ten_mins_ago = self.day_ago
         self.nine_mins_ago = self.day_ago + timedelta(minutes=1)
-        self.start = self.day_ago - timedelta(days=1)
+        self.start = (self.day_ago - timedelta(days=1)).replace(
+            hour=0, minute=0, second=0, microsecond=0
+        )
         self.end = self.start + timedelta(days=2)
 
     def test_cross_trace_query_with_logs(self) -> None: