fix: harden typed metrics review findings

crates/crank-metrics/tests/exemplars.rs

@@ -2,7 +2,7 @@ use std::time::Duration;
 
 use crank_metrics::{
     ExemplarTraceId, HttpMethod, HttpRoute, HttpStatusClass, exemplar_snapshot,
-    record_http_request_with_exemplar, reset_exemplars_for_test,
+    record_http_request_with_exemplar,
 };
 use metrics_util::debugging::DebuggingRecorder;
 
@@ -12,10 +12,16 @@ fn trace_id_is_validated_and_never_becomes_an_ordinary_label() {
     assert!(ExemplarTraceId::parse("0123456789ABCDEF0123456789ABCDEF").is_none());
     assert!(ExemplarTraceId::parse("short").is_none());
 
-    reset_exemplars_for_test();
     let recorder = DebuggingRecorder::new();
     let snapshotter = recorder.snapshotter();
     metrics::with_local_recorder(&recorder, || {
+        record_http_request_with_exemplar(
+            HttpRoute::from_matched_path("/health"),
+            HttpMethod::Get,
+            HttpStatusClass::Success,
+            Duration::ZERO,
+            ExemplarTraceId::parse("0123456789abcdef0123456789abcdef"),
+        );
         record_http_request_with_exemplar(
             HttpRoute::from_matched_path("/health"),
             HttpMethod::Get,
@@ -23,6 +29,20 @@ fn trace_id_is_validated_and_never_becomes_an_ordinary_label() {
             Duration::from_millis(10),
             ExemplarTraceId::parse("0123456789abcdef0123456789abcdef"),
         );
+        record_http_request_with_exemplar(
+            HttpRoute::from_matched_path("/health"),
+            HttpMethod::Get,
+            HttpStatusClass::Success,
+            Duration::from_secs(61),
+            ExemplarTraceId::parse("0123456789abcdef0123456789abcdef"),
+        );
+        record_http_request_with_exemplar(
+            HttpRoute::from_matched_path("/health"),
+            HttpMethod::Get,
+            HttpStatusClass::Success,
+            Duration::from_millis(10),
+            None,
+        );
     });
 
     let aggregate = snapshotter.snapshot().into_vec();
@@ -32,9 +52,17 @@ fn trace_id_is_validated_and_never_becomes_an_ordinary_label() {
             .all(|(key, _, _, _)| { key.key().labels().all(|label| label.key() != "trace_id") })
     );
     let exemplars = exemplar_snapshot();
-    assert_eq!(exemplars.len(), 1);
-    assert_eq!(
-        exemplars[0].trace_id.as_str(),
-        "0123456789abcdef0123456789abcdef"
+    assert_eq!(exemplars.len(), 3);
+    assert!(
+        exemplars
+            .iter()
+            .all(|exemplar| exemplar.trace_id.as_str() == "0123456789abcdef0123456789abcdef")
     );
+    let bounds = exemplars
+        .iter()
+        .map(|exemplar| exemplar.bucket_upper_bound)
+        .collect::<Vec<_>>();
+    assert!(bounds.contains(&Some(0.005)));
+    assert!(bounds.contains(&Some(0.01)));
+    assert!(bounds.contains(&None));
 }