The runtime's file is the runtime module's: the resolver test expects docker to write live-restore (issue 190, ADR 0196)

The catalogue moves daemon.json's live-restore and the reload from resolv-conf to the docker
module, so no module writes another software's configuration. The test composes docker beside
the resolver modules and refuses resolv-conf writing the runtime's file.

internal/catalogue/resolver_manifests_test.go

@@ -15,7 +15,8 @@ import (
 // same arrangement, and to the two things a resolver here must never do — read resolv.conf for
 // its upstreams, or take an address systemd-resolved holds.
 
-// resolverShelf is the three resolver modules beside something that answers `mesh-addressing`.
+// resolverShelf is the three resolver modules and the container runtime beside something that
+// answers `mesh-addressing`.
 // The networking module that really does is composed in the controller and cannot be imported
 // here, so a stand-in offers the same word; what is under test is the manifests, not the network.
 func resolverShelf(t *testing.T) map[string]Manifest {
@@ -23,7 +24,7 @@ func resolverShelf(t *testing.T) map[string]Manifest {
 	shelf := map[string]Manifest{
 		"net": {Module: "net", Version: "1", Provides: []Offer{{Name: "mesh-addressing"}}},
 	}
-	for _, name := range []string{"dnsmasq", "resolv-conf", "resolved-split-dns"} {
+	for _, name := range []string{"dnsmasq", "resolv-conf", "resolved-split-dns", "docker"} {
 		shelf[name] = catalogueManifest(t, name)
 	}
 	return shelf
@@ -117,8 +118,9 @@ func TestTheResolverForwardsToFixedUpstreamsAndNeverReadsResolvConf(t *testing.T
 // that file, the machine pointed at the resolver by address, and the runtime given no resolver of
 // its own but kept running across a restart (ADR 0196).
 func TestTheResolverAndWhatAsksItComposeOnOneMachine(t *testing.T) {
-	got, err := Resolve(resolverShelf(t), []string{"dnsmasq", "resolv-conf"},
+	got, err := Resolve(resolverShelf(t), []string{"dnsmasq", "resolv-conf", "docker"},
-		Node{Name: "anchor", At: "anchor.internal"}, World{})
+		Node{Name: "anchor", At: "anchor.internal", Capabilities: map[string]bool{
+			"package-manager": true, "service-manager": true, "privileged": true}}, World{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -167,13 +169,19 @@ func TestTheResolverAndWhatAsksItComposeOnOneMachine(t *testing.T) {
 		t.Errorf("the resolver was not told to forward the zone to its answerer:\n%s", z)
 	}
 
-	// The runtime's own file, written into (novox/hq ADR 0102) with one key, by what decides how the
+	// The runtime's own file, written into (novox/hq ADR 0102) with one key, by the runtime's own
-	// machine resolves: a restart keeps every container running. No `dns` — a container copies its
+	// module — a module does not write another software's configuration (issue 190): a restart keeps
-	// machine's resolvers (ADR 0196), and the mesh's resolver is not written into the runtime twice.
+	// every container running. No `dns` — a container copies its machine's resolvers (ADR 0196), and
+	// neither the resolver nor what decides how the machine resolves writes the runtime's file.
 	if ids["dnsmasq.runtime-dns"] != nil {
 		t.Errorf("the resolver still writes the runtime's dns: %v", ids["dnsmasq.runtime-dns"])
 	}
-	runtime := ids["resolv-conf.runtime-config"]
+	for id := range ids {
+		if strings.HasPrefix(id, "resolv-conf.runtime") {
+			t.Errorf("what the machine asks still writes the runtime's file: %s", id)
+		}
+	}
+	runtime := ids["docker.daemon"]
 	if runtime == nil || runtime["path"] != "/etc/docker/daemon.json" || runtime["into"] != "json" {
 		t.Fatalf("live-restore is not written into the runtime's file: %v", runtime)
 	}
@@ -195,7 +203,7 @@ func TestTheResolverAndWhatAsksItComposeOnOneMachine(t *testing.T) {
 			t.Errorf("the runtime is ordered restarted, which stops every container (ADR 0102): %v", r)
 		}
 		for _, on := range asStrings(r["reload-on"]) {
-			if on == "resolv-conf.runtime-config" {
+			if on == "docker.daemon" {
 				reloaded = true
 			}
 		}