Say what a node's bucket holds when a served composition test waits in vain (issue 1945)

cmd/mesh-controller/composed_served_integration_test.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -225,10 +226,41 @@ func (m *servedMesh) waitFor(t *testing.T, done chan error, node, key string, af
 		}
 		time.Sleep(200 * time.Millisecond)
 	}
-	t.Fatalf("%s in %s was not written within a minute", key, bucket)
+	t.Fatalf("%s in %s was not written within a minute; %s", key, bucket, m.whatIsThere(t, node))
 	return 0
 }
 
+// whatIsThere says, for a failure, what the node's bucket holds, the ids its own composition carries and the
+// fingerprints the controller has registered.
+func (m *servedMesh) whatIsThere(t *testing.T, node string) string {
+	t.Helper()
+	bucket, _ := sdkdelivery.ComposedBucketFor(node)
+	out := "keys:"
+	kv, err := m.controller.KeyValue(context.Background(), bucket)
+	if err != nil {
+		return out + " " + err.Error()
+	}
+	lister, err := kv.ListKeys(context.Background())
+	if err == nil {
+		for k := range lister.Keys() {
+			out += " " + k
+		}
+	}
+	own, _ := sdkdelivery.ComposedNodeKey(node)
+	if e, err := kv.Get(context.Background(), own); err == nil {
+		if c, err := sdkdelivery.DecodeComposed(e.Value()); err == nil {
+			out += "; its own carries:"
+			for _, r := range c.Resources {
+				var head struct{ ID string }
+				_ = json.Unmarshal(r, &head)
+				out += " " + head.ID
+			}
+		}
+	}
+	fps, err := currentFingerprints(context.Background(), m.open.inventory)
+	return out + fmt.Sprintf("; fingerprints registered: %v (%v)", fps, err)
+}
+
 // revisions are a node's composition keys and their revisions.
 func (m *servedMesh) revisions(t *testing.T, node string) map[string]uint64 {
 	t.Helper()