The merge gate refuses an artifact context naming another repository (issue 1019)

cmd/mesh-controller/merge_gate_test.go

@@ -559,3 +559,32 @@ func TestADeliveryGroupMovingAModuleMachinesRunPassesTheGate(t *testing.T) {
 		t.Errorf("the removal of a module machines run passed alone:\n%s", v.Report())
 	}
 }
+
+// **A module lives whole in one repository** (novox/hq ADR 0420 §1, issue 1019): an artifact whose build
+// context names another repository is refused by the gate, and one naming its own passes it.
+func TestTheGateRefusesAnArtifactContextNamingAnotherRepository(t *testing.T) {
+	withContext := func(repo string) string {
+		return `{"module":"proxy","version":"1","build":{"artifacts":[{"name":"server","kind":"image","from":"Dockerfile",` +
+			`"context":{"seat":"git","repository":"` + repo + `","ref":"main"}}]}}`
+	}
+	judge := func(repo string) []string {
+		t.Helper()
+		tree := aTree(t, map[string]string{"proxy": withContext(repo)})
+		_, failures, err := shelfWithChange(map[string]catalogue.Manifest{}, map[string]inventory.Source{},
+			snapshot.Facts{}, "novox/mesh-controller", tree, map[string]string{}, nil)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return failures
+	}
+	const want = "proxy builds artifact server from novox/mesh-catalog: a module lives whole in one repository (novox/hq ADR 0420 §1)"
+	failures := judge("novox/mesh-catalog")
+	if len(failures) != 1 || !strings.Contains(failures[0], want) {
+		t.Errorf("a context naming another repository: %v, want it to say %q", failures, want)
+	}
+	for _, f := range judge("novox/mesh-controller") {
+		if strings.Contains(f, "ADR 0420 §1") {
+			t.Errorf("a context naming the module's own repository was refused: %s", f)
+		}
+	}
+}