observability: ensure method is captured + tests

Author: odeke-em

observability.go

@@ -73,7 +73,7 @@ type spanWithMetrics struct {
 
 func roundtripTrackingSpan(ctx context.Context, methodName string, traceOpts ...trace.StartOption) (context.Context, *spanWithMetrics) {
 	ctx, span := trace.StartSpan(ctx, methodName, traceOpts...)
-	return ctx, &spanWithMetrics{span: span, startTime: time.Now()}
+	return ctx, &spanWithMetrics{span: span, startTime: time.Now(), method: methodName}
 }
 
 func (swm *spanWithMetrics) setError(err error) {

observability_test.go

@@ -117,7 +117,7 @@ func TestUnitRoundtripTrackingOperation(t *testing.T) {
 	} else {
 		r0 := vdLatency.Rows[0]
 		// We need to have the row with the tag "error" since we ended with an error"
-		wantTags := []tag.Tag{{Key: keyError, Value: errMsg}}
+		wantTags := []tag.Tag{{Key: keyError, Value: errMsg}, {Key: keyMethod, Value: "a.b.c/D.Foo"}}
 		if !reflect.DeepEqual(wantTags, r0.Tags) {
 			t.Errorf("Latency.ViewData.Rows[0].Tags mismatch\nGot: %#v\nWant:%#v\n", r0.Tags, wantTags)
 		}
@@ -151,7 +151,7 @@ func TestUnitRoundtripTrackingOperation(t *testing.T) {
 		t.Errorf("Calls.ViewdAta.Rows: Got %d Wanted %d", g, w)
 	} else {
 		r0 := vdCalls.Rows[0]
-		wantTags := []tag.Tag{{Key: keyError, Value: errMsg}}
+		wantTags := []tag.Tag{{Key: keyError, Value: errMsg}, {Key: keyMethod, Value: "a.b.c/D.Foo"}}
 		if !reflect.DeepEqual(wantTags, r0.Tags) {
 			t.Errorf("Calls.ViewData.Rows[0].Tags mismatch\nGot: %#v\nWant:%#v\n", r0.Tags, wantTags)
 		}