diff --git a/tests/sources/test10_8.gv b/tests/sources/test10_8.gv
new file mode 100644
index 0000000..0e80396
--- /dev/null
+++ b/tests/sources/test10_8.gv
@@ -0,0 +1,14 @@
+digraph G{
+    ordering=out;
+    {rank=same;"1";"2"};
+    "1"->"2";
+    {rank=same;"4";"5"};
+    "4"->"5";
+    "7"->"5";
+    "7"->"4";
+    "6"->"1";
+    "3"->"6";
+    "6"->"4";
+    "3"->"8";
+}
+
diff --git a/tests/sources/test11_12.gv b/tests/sources/test11_12.gv
new file mode 100644
index 0000000..21143e6
--- /dev/null
+++ b/tests/sources/test11_12.gv
@@ -0,0 +1,25 @@
+digraph G {
+size="6,6";
+	1 -> 2 -> 3;
+
+	subgraph cluster0 {
+		4 -> 5;
+		4 -> 6;
+	}
+
+	subgraph cluster1 {
+		7 -> 8;
+		7 -> 9;
+	}
+
+	subgraph cluster2 {
+		10 -> 11;
+		10 -> 12;
+	}
+
+	1 -> 4;
+	2 -> 4;
+	2 -> 5;
+	1 -> 12;
+	3 -> 11;
+}