Hold a converged declaration to the bytes main sends, captured from it, rather than to re-marshalling itself (hq ADR 0100)

cmd/mesh-controller/sendable_test.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/novox/mesh-controller/internal/catalogue"
 	"github.com/novox/mesh-controller/internal/inventory"
+	"github.com/novox/mesh-controller/internal/overlay"
 )
 
 // novox/hq ADR 0100: every declaration an adopted node is sent says it is adopted and which modules
@@ -41,13 +42,24 @@ func composed(t *testing.T, open *stores, node string) sendable {
 	return declared
 }
 
+// convergedBefore is the envelope a converged node was sent before adoption existed, captured by
+// running this same composition at the commit this branch left main (0a39b7d). The mesh here is
+// aMesh's laptop with the private network taken off it, so nothing in the declaration is random:
+// what changes this string is a change to what a converged machine is sent, which is the thing an
+// older host would refuse.
+const convergedBefore = `{"declaration":1,"resources":[{"content":"hello","id":"hello-web.page","path":"/var/lib/hello-web/index.html","type":"file"},{"hosts":["anchor.internal:10.77.0.1"],"id":"hello-web.server","image":"registry.example/hello@sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","name":"hello-web","type":"container"},{"id":"hello-web.served","path":"/var/lib/hello-web","type":"directory"}]}`
+
 func TestAConvergedDeclarationIsByteForByteWhatItWas(t *testing.T) {
 	open := aMesh(t)
+	ctx := t.Context()
 	register(t, open, helloWeb())
-	if _, err := assign(t.Context(), open, "anchor", "hello-web"); err != nil {
+	if _, err := unassign(ctx, open, "laptop", overlay.Name); err != nil {
 		t.Fatal(err)
 	}
-	declared := composed(t, open, "anchor")
+	if _, err := assign(ctx, open, "laptop", "hello-web"); err != nil {
+		t.Fatal(err)
+	}
+	declared := composed(t, open, "laptop")
 	if declared.Adoption != nil {
 		t.Fatal("a converged node was given an adoption envelope")
 	}
@@ -55,13 +67,9 @@ func TestAConvergedDeclarationIsByteForByteWhatItWas(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	// The envelope exactly as every send site marshalled it before adoption existed.
-	before, err := json.Marshal(map[string]any{"declaration": 1, "resources": declared.Resources})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !bytes.Equal(body, before) {
-		t.Fatalf("a converged declaration changed:\n%s\n%s", body, before)
+	if string(body) != convergedBefore {
+		t.Fatalf("a converged declaration changed; an older host parses this strictly:\n%s\n%s",
+			body, convergedBefore)
 	}
 	if bytes.Contains(body, []byte(`"adoption"`)) {
 		t.Fatal("a converged declaration names adoption; an older host would refuse it")