feat: build vehicle data platform and production pipeline

go/vehicle-gateway/internal/metrics/recent_latency_test.go

@@ -0,0 +1,34 @@
+package metrics
+
+import "testing"
+
+func TestRecentLatencyByKeyTracksBoundedP99PerKey(t *testing.T) {
+	tracker := NewRecentLatencyByKey(3)
+
+	p99, samples := tracker.Observe("a", 10)
+	if p99 != 10 || samples != 1 {
+		t.Fatalf("first p99=%v samples=%d", p99, samples)
+	}
+	tracker.Observe("a", 20)
+	p99, samples = tracker.Observe("a", 30)
+	if p99 != 30 || samples != 3 {
+		t.Fatalf("filled p99=%v samples=%d", p99, samples)
+	}
+	p99, samples = tracker.Observe("a", 5)
+	if p99 != 30 || samples != 3 {
+		t.Fatalf("bounded p99=%v samples=%d", p99, samples)
+	}
+	p99, samples = tracker.Observe("b", 7)
+	if p99 != 7 || samples != 1 {
+		t.Fatalf("second key p99=%v samples=%d", p99, samples)
+	}
+}
+
+func TestRecentLatencyByKeySanitizesBadValues(t *testing.T) {
+	tracker := NewRecentLatencyByKey(2)
+
+	p99, samples := tracker.Observe("", -10)
+	if p99 != 0 || samples != 1 {
+		t.Fatalf("p99=%v samples=%d", p99, samples)
+	}
+}