Updated test

Author: antonpirker

tests/test_dsc.py

@@ -218,6 +218,19 @@ def my_traces_sampler(sampling_context):
 @pytest.mark.parametrize(
     "test_data, expected_sample_rate, expected_sampled",
     [
+        # Test data:
+        # "incoming_sample_rate":
+        #       The "sentry-sample_rate" in the incoming `baggage` header.
+        # "incoming_sampled":
+        #       The "sentry-sampled" in the incoming `baggage` header.
+        # "sentry_trace_header_parent_sampled":
+        #       The number at the end in the `sentry-trace` header, called "parent_sampled".
+        # "use_local_traces_sampler":
+        #       Whether the local traces sampler is used.
+        # "local_traces_sampler_result":
+        #       The result of the local traces sampler.
+        # "local_traces_sample_rate":
+        #       The `traces_sample_rate` setting in the local `sentry_init` call.
         (
             {
                 "incoming_sample_rate": 1.0,
@@ -252,7 +265,7 @@ def my_traces_sampler(sampling_context):
                 "local_traces_sample_rate": 0.7,
             },
             None,  # expected_sample_rate
-            "tracing-disabled-no-transactions-should-be-sent",  # expected_sampled
+            "tracing-disabled-no-transactions-should-be-sent",  # expected_sampled (because the parent sampled is 0)
         ),
         (
             {
@@ -264,7 +277,7 @@ def my_traces_sampler(sampling_context):
                 "local_traces_sample_rate": 0.7,
             },
             0.5,  # expected_sample_rate
-            "false",  # expected_sampled
+            "false",  # expected_sampled (traces sampler can override parent sampled)
         ),
         (
             {
@@ -276,7 +289,7 @@ def my_traces_sampler(sampling_context):
                 "local_traces_sample_rate": None,
             },
             None,  # expected_sample_rate
-            "tracing-disabled-no-transactions-should-be-sent",  # expected_sampled
+            "tracing-disabled-no-transactions-should-be-sent",  # expected_sampled (traces_sample_rate=None disables all transaction creation)
         ),
         (
             {
@@ -288,7 +301,7 @@ def my_traces_sampler(sampling_context):
                 "local_traces_sample_rate": None,
             },
             0.5,  # expected_sample_rate
-            "true",  # expected_sampled
+            "true",  # expected_sampled (traces sampler overrides the traces_sample_rate setting, so transactions are created)
         ),
         (
             {
@@ -300,7 +313,7 @@ def my_traces_sampler(sampling_context):
                 "local_traces_sample_rate": None,
             },
             None,  # expected_sample_rate
-            "tracing-disabled-no-transactions-should-be-sent",  # expected_sampled
+            "tracing-disabled-no-transactions-should-be-sent",  # expected_sampled (traces_sample_rate=None disables all transaction creation)
         ),
         (
             {
@@ -317,7 +330,7 @@ def my_traces_sampler(sampling_context):
         (
             {
                 "incoming_sample_rate": 1.0,
-                "incoming_sampled": "true",
+                "incoming_sampled": None,
                 "sentry_trace_header_parent_sampled": None,
                 "use_local_traces_sampler": False,
                 "local_traces_sampler_result": 0.5,
@@ -330,13 +343,13 @@ def my_traces_sampler(sampling_context):
     ids=(
         "1 traces_sample_rate does not override incoming",
         "2 traces_sampler overrides incoming",
-        "3 traces_sample_rate does not overrides incoming (incoming not sampled)",
+        "3 traces_sample_rate does not overrides incoming sample rate or parent (incoming not sampled)",
         "4 traces_sampler overrides incoming (incoming not sampled)",
         "5 forwarding incoming (traces_sample_rate not set)",
         "6 traces_sampler overrides incoming  (traces_sample_rate not set)",
         "7 forwarding incoming (traces_sample_rate not set) (incoming not sampled)",
         "8 traces_sampler overrides incoming  (traces_sample_rate not set) (incoming not sampled)",
-        "9 traces_sample_rate overrides incoming",
+        "9 traces_sample_rate overrides incoming (upstream deferred sampling decision)",
     ),
 )
 def test_dsc_sample_rate_change(
@@ -408,6 +421,9 @@ def my_traces_sampler(sampling_context):
         assert dsc_in_envelope_header["trace_id"] == incoming_trace_id
 
 
+# TODO: test for dcs sample_rate upate in case of backpressure down sampling.
+
+
 def test_dsc_issue(sentry_init, capture_envelopes):
     """
     Our service is a standalone service that does not have tracing enabled. Just uses Sentry for error reporting.