fix(09): WR-05 refuse relation link and unlink the panel does not declare

modules/cabana/permissions_test.go

@@ -2,6 +2,8 @@ package cabana
 
 import (
 	"context"
+	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"git.golem15.com/golem15/summercms/modules/bouncer"
@@ -105,3 +107,37 @@ func TestNavigationDropsDeniedParentAndRepointsTarget(t *testing.T) {
 		t.Fatalf("navigation = %#v, want the parent to keep its own controller", nav)
 	}
 }
+
+// TestRelationMutationsFollowToolbarButtons pins WR-05: link and unlink are
+// refused unless the relation's view panel declares them.
+func TestRelationMutationsFollowToolbarButtons(t *testing.T) {
+	svc := phase09DeniedService()
+	cc := svc.reg.byID["acme.demo.widgets"]
+	super := &bouncer.Principal{ID: 1, Backend: true, IsSuperuser: true}
+	relation := func(buttons ...string) {
+		cc.Relations = map[string]*CompiledRelation{"editors": {Schema: &RelationSchema{Name: "editors", View: RelationPanel{ToolbarButtons: buttons}}}}
+	}
+	call := func(handler func(*service, http.ResponseWriter, *http.Request)) int {
+		rec := httptest.NewRecorder()
+		handler(svc, rec, phase09Request(super))
+		return rec.Code
+	}
+
+	relation("link")
+	if code := call((*service).relationUnlink); code != http.StatusForbidden {
+		t.Fatalf("unlink on a link-only relation = %d, want 403", code)
+	}
+	if code := call((*service).relationLink); code == http.StatusForbidden {
+		t.Fatal("link on a link-only relation was refused")
+	}
+	relation()
+	for name, handler := range map[string]func(*service, http.ResponseWriter, *http.Request){"link": (*service).relationLink, "unlink": (*service).relationUnlink} {
+		if code := call(handler); code != http.StatusForbidden {
+			t.Fatalf("%s on a relation with no buttons = %d, want 403", name, code)
+		}
+	}
+	relation("link", "unlink")
+	if code := call((*service).relationUnlink); code == http.StatusForbidden {
+		t.Fatal("unlink on a link|unlink relation was refused")
+	}
+}