diff --git a/src/main/java/kieker/analysis/graph/GraphTester.java b/src/main/java/kieker/analysis/graph/GraphTester.java
index 03566b68899f3f6e2d6cab21551ccf7edef6751b..1fb4f3ce144400679fb231cad6ae330e380de590 100644
--- a/src/main/java/kieker/analysis/graph/GraphTester.java
+++ b/src/main/java/kieker/analysis/graph/GraphTester.java
@@ -12,9 +12,28 @@ public class GraphTester {
 
 		Vertex node2 = graph.addVertex("n2");
 
-		Graph subgraph = node1.addChildGraph();
+		Vertex node3 = graph.addVertex("n3");
 
-		Vertex node11 = subgraph.addVertex("n1::n1");
+		Vertex node4 = graph.addVertex("n4");
+
+		Edge edge12 = node1.addEdge(node2);
+		Edge edge11 = node1.addEdge(node1);
+
+		Edge edge23 = node2.addEdge("e23", node3);
+
+		graph.addEdge("e13", node1, node3);
+
+		Vertex node1snd = graph.getVertex("n1");
+
+		assert node1 == node1snd;
+
+		for (Vertex vertex : graph.getVertices()) {
+			System.out.println(vertex.getId());
+		}
+
+		for (Edge edge : graph.getEdges()) {
+			System.out.println(edge.getId());
+		}
 
 		// node2.addEdgeTo(node11);
 
diff --git a/src/main/java/kieker/analysis/graph/impl/GraphImpl.java b/src/main/java/kieker/analysis/graph/impl/GraphImpl.java
index 2ea509212de51c7786fc22661ecb81ffcd58b002..580a808d2656bb4bc8bf9631b3a61a87c7333009 100644
--- a/src/main/java/kieker/analysis/graph/impl/GraphImpl.java
+++ b/src/main/java/kieker/analysis/graph/impl/GraphImpl.java
@@ -78,6 +78,8 @@ public class GraphImpl implements Graph {
 			}
 		}
 
+		// TODO Maybe: Check whether both vertices are in the same graph
+
 		final Edge edge = new EdgeImpl(idString, outVertex, inVertex, this);
 		this.edges.put(edge.getId().toString(), edge);
 		((VertexImpl) outVertex).addOutEdge(edge);