diff --git a/gap/gv.gi b/gap/gv.gi
index 8ec4c77..bf123de 100644
--- a/gap/gv.gi
+++ b/gap/gv.gi
@@ -239,6 +239,18 @@ function(graph)
   return graph;
 end);
 
+BindGlobal("GV_Indent", lvl -> ListWithIdenticalEntries(2 * lvl, ' '));
+
+BindGlobal("GV_Depth", function(gv)
+  local depth;
+  depth := 0;
+  while GV_GetParent(gv) <> fail do
+    gv := GV_GetParent(gv);
+    depth := depth + 1;
+  od;
+  return depth;
+end);
+
 InstallMethod(GV_AddNode,
 "for a graphviz graph and node",
 [IsGraphvizGraphDigraphOrContext, IsGraphvizNode],
@@ -272,11 +284,17 @@ graph -> StringFormatted("digraph {} {{\n", GraphvizName(graph)));
 
 # @ Return DOT subgraph head line.
 BindGlobal("GV_StringifySubgraphHead",
-graph -> StringFormatted("subgraph {} {{\n", GraphvizName(graph)));
+gv -> StringFormatted("{}subgraph {} {{\n", GV_Indent(GV_Depth(gv)), GraphvizName(gv)));
 
 # @ Return DOT subgraph head line.
 BindGlobal("GV_StringifyContextHead",
-graph -> StringFormatted("// {} context \n{{\n", GraphvizName(graph)));
+function(gv)
+  local indent;
+  indent := GV_Indent(GV_Depth(gv));
+  return StringFormatted("{1}{{\n{1}  // context \"{2}\" \n",
+                         indent,
+                         GraphvizName(gv));
+end);
 
 BindGlobal("GV_StringifyNodeName",
 function(node)
@@ -289,13 +307,7 @@ function(node)
       and not StartsWith(name, "\"") then
     old  := name;
     name := StringFormatted("\"{}\"", name);
-    Info(InfoWarning,
-         1,
-         "invalid node name ",
-         old,
-         " using ",
-         name,
-         " instead");
+    Info(InfoWarning, 1, "invalid node name ", old, " using ", name, " instead");
   fi;
   return name;
 end);
@@ -339,7 +351,10 @@ function(node)
   local name, attrs;
   name  := GV_StringifyNodeName(node);
   attrs := GraphvizAttrs(node);
-  return StringFormatted("\t{}{}\n", name, GV_StringifyAttrList(attrs));
+  return StringFormatted("{}{}{}\n",
+                         GV_Indent(GV_Depth(node)),
+                         name,
+                         GV_StringifyAttrList(attrs));
 end);
 
 # @ Return DOT graph edge statement line.
@@ -353,7 +368,8 @@ function(edge, edge_str)
   attrs := GraphvizAttrs(edge);
 
   # handle : syntax
-  return StringFormatted("\t{} {} {}{}\n",
+  return StringFormatted("{}{} {} {}{}\n",
+                         GV_Indent(GV_Depth(edge)),
                          head,
                          edge_str,
                          tail,
@@ -413,7 +429,11 @@ function(graph, is_subgraph)
   for type in ["graph", "node", "edge"] do
     record := GraphvizAttrs(graph).(type);
     if Length(RecNames(record)) > 0 then
-      Append(result, StringFormatted("{} {}\n", type, GV_StringifyAttrList(record)));
+      Append(result,
+        StringFormatted("{}{}{}\n",
+                        GV_Indent(GV_Depth(graph) + 1),
+                        type,
+                        GV_StringifyAttrList(record)));
     fi;
   od;
 
@@ -432,7 +452,10 @@ function(graph, is_subgraph)
     fi;
   od;
 
-  Append(result, "}\n");
+  Append(result, StringFormatted("{}}}", GV_Indent(GV_Depth(graph))));
+  if GV_Depth(graph) > 0 then
+    Append(result, "\n");
+  fi;
   return result;
 end);
 
diff --git a/tst/dot.tst b/tst/dot.tst
index b2e32a8..619f223 100644
--- a/tst/dot.tst
+++ b/tst/dot.tst
@@ -38,8 +38,11 @@ rec( edge := rec(  ),
 gap> g := GraphvizGraph();;
 gap> n := GraphvizAddNode(g, "test");;
 gap> GraphvizSetAttrs(n, rec(color := "red", label := "lab"));;
-gap> AsString(g);
-"//dot\ngraph  {\n\ttest [color=\"red\", label=\"lab\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  test [color="red", label="lab"]
+}
 gap> GraphvizRemoveNode(g, "banana");
 Error, the 2nd argument (node name string) "banana" is not a node of the 1st a\
 rgument (a graphviz (di)graph/context)
@@ -52,9 +55,13 @@ gap> GraphvizSetAttrs(a, rec(color := "blue"));;
 gap> GraphvizSetAttrs(b, rec(color := "red"));;
 gap> e := GraphvizAddEdge(g, a, b);;
 gap> GraphvizSetAttrs(e, rec(color := "green"));;
-gap> AsString(g);
-"//dot\ndigraph  {\n\ta [color=\"blue\"]\n\tb [color=\"red\"]\n\ta -> b [color\
-=\"green\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph  {
+  a [color="blue"]
+  b [color="red"]
+  a -> b [color="green"]
+}
 
 # Test stringify with edge (graph)
 gap> g := GraphvizGraph();;
@@ -64,14 +71,20 @@ gap> GraphvizSetAttrs(a, rec(color := "blue"));;
 gap> GraphvizSetAttrs(b, rec(color := "red"));;
 gap> e := GraphvizAddEdge(g, a, b);;
 gap> GraphvizSetAttrs(e, rec(color := "green"));;
-gap> AsString(g);
-"//dot\ngraph  {\n\ta [color=\"blue\"]\n\tb [color=\"red\"]\n\ta -- b [color=\
-\"green\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  a [color="blue"]
+  b [color="red"]
+  a -- b [color="green"]
+}
 
 # Test stringify empty
 gap> g := GraphvizGraph();;
-gap> AsString(g);
-"//dot\ngraph  {\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+}
 
 # Test unknown attributes (node)
 gap> g := GraphvizGraph();;
@@ -88,25 +101,41 @@ gap> GraphvizSetAttr(g, "test", "false");
 gap> g := GraphvizGraph();;
 gap> n := GraphvizAddNode(g, "node");;
 gap> GraphvizSetAttr(n, "label", ">>hello");;
-gap> AsString(g);
-"//dot\ngraph  {\n\tnode [label=\">>hello\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  node [label=">>hello"]
+}
 gap> g := GraphvizGraph();;
 gap> n := GraphvizAddNode(g, "node");;
 gap> GraphvizSetAttr(n, "label", "before>>hello");;
-gap> AsString(g);
-"//dot\ngraph  {\n\tnode [label=\"before>>hello\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  node [label="before>>hello"]
+}
 
 # Test strngifying labels with ">>" inside (edge attrs)
 gap> g := GraphvizGraph();;
 gap> e := GraphvizAddEdge(g, "a", "b");;
 gap> GraphvizSetAttr(e, "label", ">>hello");;
-gap> AsString(g);
-"//dot\ngraph  {\n\ta\n\tb\n\ta -- b [label=\">>hello\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  a
+  b
+  a -- b [label=">>hello"]
+}
 gap> g := GraphvizGraph();;
 gap> e := GraphvizAddEdge(g, "a", "b");;
 gap> GraphvizSetAttr(e, "label", "before>>hello");;
-gap> AsString(g);
-"//dot\ngraph  {\n\ta\n\tb\n\ta -- b [label=\"before>>hello\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  a
+  b
+  a -- b [label="before>>hello"]
+}
 
 # Test GraphvizSetNodeLabels
 gap> gv := GraphvizGraph("xxx");
@@ -119,21 +148,21 @@ gap> GraphvizAddNode(gv, 3);
 <graphviz node "3">
 gap> GraphvizSetNodeLabels(gv, ["i", "ii", "iii"]);
 <graphviz graph "xxx" with 3 nodes and 0 edges>
-gap> Print(AsString(gv));
+gap> Print(AsString(gv), "\n");
 //dot
 graph xxx {
-	1 [label="i"]
-	2 [label="ii"]
-	3 [label="iii"]
+  1 [label="i"]
+  2 [label="ii"]
+  3 [label="iii"]
 }
 gap> GraphvizSetNodeLabels(gv, ["a", "b", "c"]);
 <graphviz graph "xxx" with 3 nodes and 0 edges>
-gap> Print(AsString(gv));
+gap> Print(AsString(gv), "\n");
 //dot
 graph xxx {
-	1 [label="a"]
-	2 [label="b"]
-	3 [label="c"]
+  1 [label="a"]
+  2 [label="b"]
+  3 [label="c"]
 }
 gap> GraphvizSetNodeLabels(gv, ["i", "ii"]);
 Error, the 2nd argument (list of node labels) has incorrect length, expected 3\
@@ -157,30 +186,30 @@ Error, invalid color "i" (list (string)), valid colors are RGB values or names\
 .html
 gap> GraphvizSetNodeColors(gv, ["red", "green", "blue"]);
 <graphviz graph "xxx" with 3 nodes and 0 edges>
-gap> Print(AsString(gv));
+gap> Print(AsString(gv), "\n");
 //dot
 graph xxx {
-	1 [color="red", style="filled"]
-	2 [color="green", style="filled"]
-	3 [color="blue", style="filled"]
+  1 [color="red", style="filled"]
+  2 [color="green", style="filled"]
+  3 [color="blue", style="filled"]
 }
 gap> GraphvizSetNodeColors(gv, ["red", "#00FF00", "blue"]);
 <graphviz graph "xxx" with 3 nodes and 0 edges>
-gap> Print(AsString(gv));
+gap> Print(AsString(gv), "\n");
 //dot
 graph xxx {
-	1 [color="red", style="filled"]
-	2 [color="#00FF00", style="filled"]
-	3 [color="blue", style="filled"]
+  1 [color="red", style="filled"]
+  2 [color="#00FF00", style="filled"]
+  3 [color="blue", style="filled"]
 }
 gap> GraphvizSetNodeColors(gv, ["#FF0000", "#00FF00", "#0000FF"]);
 <graphviz graph "xxx" with 3 nodes and 0 edges>
-gap> Print(AsString(gv));
+gap> Print(AsString(gv), "\n");
 //dot
 graph xxx {
-	1 [color="#FF0000", style="filled"]
-	2 [color="#00FF00", style="filled"]
-	3 [color="#0000FF", style="filled"]
+  1 [color="#FF0000", style="filled"]
+  2 [color="#00FF00", style="filled"]
+  3 [color="#0000FF", style="filled"]
 }
 gap> GraphvizSetNodeColors(gv, ["#FF0000", "#00FF00", "#0000FG"]);
 Error, invalid color "#0000FG" (list (string)), valid colors are RGB values or\
@@ -206,14 +235,14 @@ gap> n := GraphvizSetAttr(n, "probably not ok", 1);
 gap> Print(AsString(gv : invalidDOT := "unquoted attribute name with spaces"), "\n");
 //dot
 graph xxx {
-	1 [probably not ok="1"]
+  1 [probably not ok="1"]
 }
 gap> GraphvizSetAttr(n, "label", "<<>>");
 <graphviz node "1">
 gap> Print(AsString(gv : invalidDOT := "unquoted attribute name with spaces"), "\n");
 //dot
 graph xxx {
-	1 [label="<<>>", probably not ok="1"]
+  1 [label="<<>>", probably not ok="1"]
 }
 
 # Issue 68
@@ -223,14 +252,25 @@ gap> a := GraphvizAddNode(g, "a");
 <graphviz node "a">
 gap> e := GraphvizAddEdge(g, a, "b");
 <graphviz edge (a, b)>
-gap> GraphvizNodes(g); AsString(g);
+gap> GraphvizNodes(g); Print(AsString(g), "\n");
 rec( a := <graphviz node "a">, b := <graphviz node "b"> )
-"//dot\ndigraph unexpected {\n\ta\n\tb\n\ta -> b\n}\n"
+//dot
+digraph unexpected {
+  a
+  b
+  a -> b
+}
 gap> e := GraphvizAddEdge(g, "b", a);
 <graphviz edge (b, a)>
-gap> GraphvizNodes(g); AsString(g);
+gap> GraphvizNodes(g); Print(AsString(g), "\n");
 rec( a := <graphviz node "a">, b := <graphviz node "b"> )
-"//dot\ndigraph unexpected {\n\ta\n\tb\n\ta -> b\n\tb -> a\n}\n"
+//dot
+digraph unexpected {
+  a
+  b
+  a -> b
+  b -> a
+}
 
 #
 gap> STOP_TEST("graphviz package: dot.tst", 0);
diff --git a/tst/examples/angles.tst b/tst/examples/angles.tst
index 43417c0..b49a1a1 100644
--- a/tst/examples/angles.tst
+++ b/tst/examples/angles.tst
@@ -67,41 +67,41 @@ gap> GraphvizSetAttr(cluster2, "label",
 <graphviz digraph "cluster_2" with 9 nodes and 0 edges>
 gap> GraphvizAddEdge(g, "n5", "n14");
 <graphviz edge (n5, n14)>
-gap> Print(AsString(g));
+gap> Print(AsString(g), "\n");
 //dot
 digraph G {
-graph  [bgcolor="blue"]
-subgraph cluster_1 {
-graph  [fontcolor="white", label="Linear Angle Variations (white to black grad\
-ient)"]
-node  [fillcolor="white:black", fontcolor="black", gradientangle="360", label=\
-"n9:n360", shape="circle", style="filled"]
-	n9
-	n8 [gradientangle="315", label="n8:315"]
-	n7 [gradientangle="270", label="n7:270"]
-	n6 [gradientangle="225", label="n6:225"]
-	n5 [gradientangle="180", label="n5:180"]
-	n4 [gradientangle="135", label="n4:135"]
-	n3 [gradientangle="90", label="n3:90"]
-	n2 [gradientangle="45", label="n2:45"]
-	n1 [gradientangle="0", label="n1:0"]
-}
-subgraph cluster_2 {
-graph  [fontcolor="white", label="Radial Angle Variations (white to black grad\
-ient)"]
-node  [fillcolor="white:black", fontcolor="black", gradientangle="360", label=\
-"n9:n360", shape="circle", style="radial"]
-	n18
-	n17 [gradientangle="315", label="n17:315"]
-	n16 [gradientangle="270", label="n16:270"]
-	n15 [gradientangle="225", label="n15:225"]
-	n14 [gradientangle="180", label="n14:180"]
-	n13 [gradientangle="135", label="n13:135"]
-	n12 [gradientangle="90", label="n12:90"]
-	n11 [gradientangle="45", label="n11:45"]
-	n10 [gradientangle="0", label="n10:0"]
-}
-	n5 -> n14
+  graph [bgcolor="blue"]
+  subgraph cluster_1 {
+    graph [fontcolor="white", label="Linear Angle Variations (white to black g\
+radient)"]
+    node [fillcolor="white:black", fontcolor="black", gradientangle="360", lab\
+el="n9:n360", shape="circle", style="filled"]
+    n9
+    n8 [gradientangle="315", label="n8:315"]
+    n7 [gradientangle="270", label="n7:270"]
+    n6 [gradientangle="225", label="n6:225"]
+    n5 [gradientangle="180", label="n5:180"]
+    n4 [gradientangle="135", label="n4:135"]
+    n3 [gradientangle="90", label="n3:90"]
+    n2 [gradientangle="45", label="n2:45"]
+    n1 [gradientangle="0", label="n1:0"]
+  }
+  subgraph cluster_2 {
+    graph [fontcolor="white", label="Radial Angle Variations (white to black g\
+radient)"]
+    node [fillcolor="white:black", fontcolor="black", gradientangle="360", lab\
+el="n9:n360", shape="circle", style="radial"]
+    n18
+    n17 [gradientangle="315", label="n17:315"]
+    n16 [gradientangle="270", label="n16:270"]
+    n15 [gradientangle="225", label="n15:225"]
+    n14 [gradientangle="180", label="n14:180"]
+    n13 [gradientangle="135", label="n13:135"]
+    n12 [gradientangle="90", label="n12:90"]
+    n11 [gradientangle="45", label="n11:45"]
+    n10 [gradientangle="0", label="n10:0"]
+  }
+  n5 -> n14
 }
 
 #
diff --git a/tst/examples/btree.tst b/tst/examples/btree.tst
index ecc45f0..a975a66 100644
--- a/tst/examples/btree.tst
+++ b/tst/examples/btree.tst
@@ -55,19 +55,44 @@ gap> GraphvizAddEdge(s, "node4:f2", "node6:f1");
 <graphviz edge (node4:f2, node6:f1)>
 gap> GraphvizAddEdge(s, "node4:f0", "node5:f1");
 <graphviz edge (node4:f0, node5:f1)>
-gap> AsString(s) =
-> "//dot\ndigraph g {\nnode  [height=\".1\", shape=\"record\"]\n\tnode0 [label=\
-> \"<f0> |<f1> G|<f2>\"]\n\tnode1 [label=\"<f0> |<f1> E|<f2>\"]\n\tnode2 [label=\
-> \"<f0> |<f1> B|<f2>\"]\n\tnode3 [label=\"<f0> |<f1> F|<f2>\"]\n\tnode4 [label=\
-> \"<f0> |<f1> R|<f2>\"]\n\tnode5 [label=\"<f0> |<f1> H|<f2>\"]\n\tnode6 [label=\
-> \"<f0> |<f1> Y|<f2>\"]\n\tnode7 [label=\"<f0> |<f1> A|<f2>\"]\n\tnode8 [label=\
-> \"<f0> |<f1> C|<f2>\"]\n\tnode0:f2\n\tnode4:f1\n\tnode0:f2 -> node4:f1\n\tnode\
-> 0:f0\n\tnode1:f1\n\tnode0:f0 -> node1:f1\n\tnode1:f0\n\tnode2:f1\n\tnode1:f0 -\
-> > node2:f1\n\tnode1:f2\n\tnode3:f1\n\tnode1:f2 -> node3:f1\n\tnode2:f2\n\tnode\
-> 8:f1\n\tnode2:f2 -> node8:f1\n\tnode2:f0\n\tnode7:f1\n\tnode2:f0 -> node7:f1\n\
-> \tnode4:f2\n\tnode6:f1\n\tnode4:f2 -> node6:f1\n\tnode4:f0\n\tnode5:f1\n\tnode\
-> 4:f0 -> node5:f1\n}\n";
-true
+gap> Print(AsString(s), "\n");
+//dot
+digraph g {
+  node [height=".1", shape="record"]
+  node0 [label="<f0> |<f1> G|<f2>"]
+  node1 [label="<f0> |<f1> E|<f2>"]
+  node2 [label="<f0> |<f1> B|<f2>"]
+  node3 [label="<f0> |<f1> F|<f2>"]
+  node4 [label="<f0> |<f1> R|<f2>"]
+  node5 [label="<f0> |<f1> H|<f2>"]
+  node6 [label="<f0> |<f1> Y|<f2>"]
+  node7 [label="<f0> |<f1> A|<f2>"]
+  node8 [label="<f0> |<f1> C|<f2>"]
+  node0:f2
+  node4:f1
+  node0:f2 -> node4:f1
+  node0:f0
+  node1:f1
+  node0:f0 -> node1:f1
+  node1:f0
+  node2:f1
+  node1:f0 -> node2:f1
+  node1:f2
+  node3:f1
+  node1:f2 -> node3:f1
+  node2:f2
+  node8:f1
+  node2:f2 -> node8:f1
+  node2:f0
+  node7:f1
+  node2:f0 -> node7:f1
+  node4:f2
+  node6:f1
+  node4:f2 -> node6:f1
+  node4:f0
+  node5:f1
+  node4:f0 -> node5:f1
+}
 
 #
 gap> STOP_TEST("graphviz package: btree.tst");
diff --git a/tst/examples/cluster.tst b/tst/examples/cluster.tst
index b1c97a5..3f7d99d 100644
--- a/tst/examples/cluster.tst
+++ b/tst/examples/cluster.tst
@@ -74,14 +74,41 @@ gap> GraphvizSetAttr(GraphvizNode(graph, "end"), "shape", "Msquare");
 <graphviz node "end">
 
 #
-gap> AsString(graph);
-"//dot\ndigraph G {\nsubgraph cluster_0 {\ngraph  [color=\"lightgrey\", label=\
-\"process #1\", style=\"filled\"]\nnode  [color=\"white\", style=\"filled\"]\n\
-\ta0\n\ta1\n\ta0 -> a1\n\ta2\n\ta1 -> a2\n\ta3\n\ta2 -> a3\n}\nsubgraph cluste\
-r_1 {\ngraph  [color=\"blue\", label=\"process #2\"]\nnode  [style=\"filled\"]\
-\n\tb0\n\tb1\n\tb0 -> b1\n\tb2\n\tb1 -> b2\n\tb3\n\tb2 -> b3\n}\n\tstart [shap\
-e=\"Mdiamond\"]\n\tstart -> a0\n\tstart -> b0\n\ta1 -> b3\n\tb2 -> a3\n\ta3 ->\
- a0\n\tend [shape=\"Msquare\"]\n\ta3 -> end\n\tb3 -> end\n}\n"
+gap> Print(AsString(graph), "\n");
+//dot
+digraph G {
+  subgraph cluster_0 {
+    graph [color="lightgrey", label="process #1", style="filled"]
+    node [color="white", style="filled"]
+    a0
+    a1
+    a0 -> a1
+    a2
+    a1 -> a2
+    a3
+    a2 -> a3
+  }
+  subgraph cluster_1 {
+    graph [color="blue", label="process #2"]
+    node [style="filled"]
+    b0
+    b1
+    b0 -> b1
+    b2
+    b1 -> b2
+    b3
+    b2 -> b3
+  }
+  start [shape="Mdiamond"]
+  start -> a0
+  start -> b0
+  a1 -> b3
+  b2 -> a3
+  a3 -> a0
+  end [shape="Msquare"]
+  a3 -> end
+  b3 -> end
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/cluster.tst");
diff --git a/tst/examples/cluster_edge.tst b/tst/examples/cluster_edge.tst
index 0a931e5..b8c567b 100644
--- a/tst/examples/cluster_edge.tst
+++ b/tst/examples/cluster_edge.tst
@@ -53,12 +53,34 @@ gap> GraphvizSetAttr(e, "ltail", "cluster0");
 <graphviz edge (c, e)>
 gap> GraphvizAddEdge(g, "d", "h");
 <graphviz edge (d, h)>
-gap> AsString(g);
-"//dot\ndigraph G {\ngraph  [compound=\"true\"]\nsubgraph cluster0 {\n\ta\n\tb\
-\n\ta -> b\n\tc\n\ta -> c\n\td\n\tb -> d\n\tc -> d\n}\nsubgraph cluster1 {\n\t\
-e\n\tg\n\te -> g\n\tf\n\te -> f\n}\n\tb -> f [lhead=\"cluster1\"]\n\td -> e\n\
-\tc -> g [lhead=\"cluster1\", ltail=\"cluster0\"]\n\tc -> e [ltail=\"cluster0\
-\"]\n\th\n\td -> h\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph G {
+  graph [compound="true"]
+  subgraph cluster0 {
+    a
+    b
+    a -> b
+    c
+    a -> c
+    d
+    b -> d
+    c -> d
+  }
+  subgraph cluster1 {
+    e
+    g
+    e -> g
+    f
+    e -> f
+  }
+  b -> f [lhead="cluster1"]
+  d -> e
+  c -> g [lhead="cluster1", ltail="cluster0"]
+  c -> e [ltail="cluster0"]
+  h
+  d -> h
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/cluster_edge.tst");
diff --git a/tst/examples/colors.tst b/tst/examples/colors.tst
index a7bf9d4..157d294 100644
--- a/tst/examples/colors.tst
+++ b/tst/examples/colors.tst
@@ -54,15 +54,18 @@ gap> GraphvizSetAttr(node, "fillcolor", "deeppink");
 <graphviz node "name: deeppink">
 
 #
-gap> AsString(g);
+gap> Print(AsString(g), "\n");
 #I  invalid node name RGB: #40e0d0 using "RGB: #40e0d0" instead
 #I  invalid node name RGBA: #ff000042 using "RGBA: #ff000042" instead
 #I  invalid node name HSV: 0.051 0.718 0.627 using "HSV: 0.051 0.718 0.627" instead
 #I  invalid node name name: deeppink using "name: deeppink" instead
-"//dot\ngraph  {\n\t\"RGB: #40e0d0\" [fillcolor=\"#40e0d0\", style=\"filled\"]\
-\n\t\"RGBA: #ff000042\" [fillcolor=\"#ff000042\", style=\"filled\"]\n\t\"HSV: \
-0.051 0.718 0.627\" [fillcolor=\"0.051 0.718 0.627\", style=\"filled\"]\n\t\"n\
-ame: deeppink\" [fillcolor=\"deeppink\", style=\"filled\"]\n}\n"
+//dot
+graph  {
+  "RGB: #40e0d0" [fillcolor="#40e0d0", style="filled"]
+  "RGBA: #ff000042" [fillcolor="#ff000042", style="filled"]
+  "HSV: 0.051 0.718 0.627" [fillcolor="0.051 0.718 0.627", style="filled"]
+  "name: deeppink" [fillcolor="deeppink", style="filled"]
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/colors.tst");
diff --git a/tst/examples/er.tst b/tst/examples/er.tst
index c4fb0ef..508e8e2 100644
--- a/tst/examples/er.tst
+++ b/tst/examples/er.tst
@@ -10,8 +10,6 @@
 
 # https://graphviz.readthedocs.io/en/stable/examples.html
 # https://graphviz.org/Gallery/undirected/ER.html
-
-#@local context1, context2, e, label, len, start
 gap> START_TEST("graphviz package: examples/er.tst");
 gap> LoadPackage("GraphvizForGAP");
 true
@@ -104,7 +102,7 @@ gap> GraphvizSetAttrs(e, rec(fontsize := "20"));
 <graphviz graph "ER" with 12 nodes and 12 edges>
 
 #
-gap> AsString(e);
+gap> Print(AsString(e), "\n");
 #I  invalid node name C-I using "C-I" instead
 #I  invalid node name S-C using "S-C" instead
 #I  invalid node name S-I using "S-I" instead
@@ -114,18 +112,47 @@ gap> AsString(e);
 #I  invalid node name S-I using "S-I" instead
 #I  invalid node name S-C using "S-C" instead
 #I  invalid node name S-C using "S-C" instead
-"//dot\ngraph ER {\ngraph  [engine=\"neato\", fontsize=\"20\", label=\"Entity \
-Relation Diagram\ndrawn by NEATO\"]\n// context_start context \n{\nnode  [shap\
-e=\"box\"]\n\tcourse\n\tinstitute\n\tstudent\n}\n// context1 context \n{\nnode\
-  [shape=\"ellipse\"]\n\tname0 [label=\"name\"]\n\tname1 [label=\"name\"]\n\tn\
-ame2 [label=\"name\"]\n\tcode\n\tgrade\n\tnumber\n}\n// context2 context \n{\n\
-node  [color=\"lightgrey\", shape=\"diamond\", style=\"filled\"]\n\t\"C-I\"\n\
-\t\"S-C\"\n\t\"S-I\"\n}\n\tname0 -- course\n\tcode -- course\n\t\"C-I\" -- cou\
-rse [label=\"n\", len=\"1.00\"]\n\tinstitute -- \"C-I\" [label=\"1\", len=\"1.\
-00\"]\n\tname1 -- institute\n\t\"S-I\" -- institute [label=\"1\", len=\"1.00\"\
-]\n\tstudent -- \"S-I\" [label=\"n\", len=\"1.00\"]\n\tgrade -- student\n\tnam\
-e2 -- student\n\tnumber -- student\n\t\"S-C\" -- student [label=\"m\", len=\"1\
-.00\"]\n\tcourse -- \"S-C\" [label=\"n\", len=\"1.00\"]\n}\n"
+//dot
+graph ER {
+  graph [engine="neato", fontsize="20", label="Entity Relation Diagram
+drawn by NEATO"]
+  {
+    // context "context_start" 
+    node [shape="box"]
+    course
+    institute
+    student
+  }
+  {
+    // context "context1" 
+    node [shape="ellipse"]
+    name0 [label="name"]
+    name1 [label="name"]
+    name2 [label="name"]
+    code
+    grade
+    number
+  }
+  {
+    // context "context2" 
+    node [color="lightgrey", shape="diamond", style="filled"]
+    "C-I"
+    "S-C"
+    "S-I"
+  }
+  name0 -- course
+  code -- course
+  "C-I" -- course [label="n", len="1.00"]
+  institute -- "C-I" [label="1", len="1.00"]
+  name1 -- institute
+  "S-I" -- institute [label="1", len="1.00"]
+  student -- "S-I" [label="n", len="1.00"]
+  grade -- student
+  name2 -- student
+  number -- student
+  "S-C" -- student [label="m", len="1.00"]
+  course -- "S-C" [label="n", len="1.00"]
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/er.tst");
diff --git a/tst/examples/fsm.tst b/tst/examples/fsm.tst
index ec10d81..c135252 100644
--- a/tst/examples/fsm.tst
+++ b/tst/examples/fsm.tst
@@ -73,17 +73,42 @@ gap> GraphvizSetAttr(GraphvizAddEdge(nodes, "LR_8", "LR_5"), "label", "\"S(a)\""
 <graphviz edge (LR_8, LR_5)>
 
 #
-gap> AsString(f);
-"//dot\ndigraph finite_state_machine {\ngraph  [rankdir=\"LR\", size=\"8,5\"]\
-\n// terminals context \n{\nnode  [shape=\"doublecircle\"]\n\tLR_0\n\tLR_3\n\t\
-LR_4\n\tLR_8\n}\n// nodes context \n{\nnode  [shape=\"circle\"]\n\tLR_2\n\tLR_\
-0 -> LR_2 [label=\"SS(B)\"]\n\tLR_1\n\tLR_0 -> LR_1 [label=\"SS(S)\"]\n\tLR_1 \
--> LR_3 [label=\"S($end)\"]\n\tLR_6\n\tLR_2 -> LR_6 [label=\"SS(b)\"]\n\tLR_5\
-\n\tLR_2 -> LR_5 [label=\"SS(a)\"]\n\tLR_2 -> LR_4 [label=\"S(A)\"]\n\tLR_7\n\
-\tLR_5 -> LR_7 [label=\"S(b)\"]\n\tLR_5 -> LR_5 [label=\"S(a)\"]\n\tLR_6 -> LR\
-_6 [label=\"S(b)\"]\n\tLR_6 -> LR_5 [label=\"S(a)\"]\n\tLR_7 -> LR_8 [label=\"\
-S(b)\"]\n\tLR_7 -> LR_5 [label=\"S(a)\"]\n\tLR_8 -> LR_6 [label=\"S(b)\"]\n\tL\
-R_8 -> LR_5 [label=\"S(a)\"]\n}\n}\n"
+gap> Print(AsString(f), "\n");
+//dot
+digraph finite_state_machine {
+  graph [rankdir="LR", size="8,5"]
+  {
+    // context "terminals" 
+    node [shape="doublecircle"]
+    LR_0
+    LR_3
+    LR_4
+    LR_8
+  }
+  {
+    // context "nodes" 
+    node [shape="circle"]
+    LR_2
+    LR_0 -> LR_2 [label="SS(B)"]
+    LR_1
+    LR_0 -> LR_1 [label="SS(S)"]
+    LR_1 -> LR_3 [label="S($end)"]
+    LR_6
+    LR_2 -> LR_6 [label="SS(b)"]
+    LR_5
+    LR_2 -> LR_5 [label="SS(a)"]
+    LR_2 -> LR_4 [label="S(A)"]
+    LR_7
+    LR_5 -> LR_7 [label="S(b)"]
+    LR_5 -> LR_5 [label="S(a)"]
+    LR_6 -> LR_6 [label="S(b)"]
+    LR_6 -> LR_5 [label="S(a)"]
+    LR_7 -> LR_8 [label="S(b)"]
+    LR_7 -> LR_5 [label="S(a)"]
+    LR_8 -> LR_6 [label="S(b)"]
+    LR_8 -> LR_5 [label="S(a)"]
+  }
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/fsm.tst");
diff --git a/tst/examples/g_c_n.tst b/tst/examples/g_c_n.tst
index b555a79..cc60611 100644
--- a/tst/examples/g_c_n.tst
+++ b/tst/examples/g_c_n.tst
@@ -33,17 +33,17 @@ gap> GraphvizSetAttrs(cluster1,
 <graphviz graph "cluster1" with 0 nodes and 0 edges>
 gap> GraphvizAddNode(cluster1, "anode");
 <graphviz node "anode">
-gap> Print(AsString(g));
+gap> Print(AsString(g), "\n");
 //dot
 graph G {
-graph  [bgcolor="purple:pink", fontcolor="white", label="agraph"]
-subgraph cluster1 {
-graph  [fillcolor="blue:cyan", fontcolor="white", gradientangle="270", label="\
-acluster", style="filled"]
-node  [fillcolor="red:yellow", gradientangle="90", shape="box", style="filled"\
-]
-	anode
-}
+  graph [bgcolor="purple:pink", fontcolor="white", label="agraph"]
+  subgraph cluster1 {
+    graph [fillcolor="blue:cyan", fontcolor="white", gradientangle="270", labe\
+l="acluster", style="filled"]
+    node [fillcolor="red:yellow", gradientangle="90", shape="box", style="fill\
+ed"]
+    anode
+  }
 }
 
 #
diff --git a/tst/examples/hello.tst b/tst/examples/hello.tst
index daee715..b30cc9d 100644
--- a/tst/examples/hello.tst
+++ b/tst/examples/hello.tst
@@ -20,8 +20,13 @@ gap> graph := GraphvizDigraph("G");
 <graphviz digraph "G" with 0 nodes and 0 edges>
 gap> GraphvizAddEdge(graph, "hello", "world");
 <graphviz edge (hello, world)>
-gap> AsString(graph);
-"//dot\ndigraph G {\n\thello\n\tworld\n\thello -> world\n}\n"
+gap> Print(AsString(graph), "\n");
+//dot
+digraph G {
+  hello
+  world
+  hello -> world
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/hello.tst");
diff --git a/tst/examples/process.tst b/tst/examples/process.tst
index 0cfbd9c..e4f4b70 100644
--- a/tst/examples/process.tst
+++ b/tst/examples/process.tst
@@ -47,12 +47,33 @@ gap> GraphvizAddEdge(graph, "runswap", "runmem");
 <graphviz edge (runswap, runmem)>
 gap> GraphvizAddEdge(graph, "new", "runmem");
 <graphviz edge (new, runmem)>
-gap> AsString(graph);
-"//dot\ngraph G {\ngraph  [engine=\"sfdp\"]\n\trun\n\tintr\n\trun -- intr\n\tr\
-unbl\n\tintr -- runbl\n\trunbl -- run\n\tkernel\n\trun -- kernel\n\tzombie\n\t\
-kernel -- zombie\n\tsleep\n\tkernel -- sleep\n\trunmem\n\tkernel -- runmem\n\t\
-swap\n\tsleep -- swap\n\trunswap\n\tswap -- runswap\n\tnew\n\trunswap -- new\n\
-\trunswap -- runmem\n\tnew -- runmem\n}\n"
+gap> Print(AsString(graph), "\n");
+//dot
+graph G {
+  graph [engine="sfdp"]
+  run
+  intr
+  run -- intr
+  runbl
+  intr -- runbl
+  runbl -- run
+  kernel
+  run -- kernel
+  zombie
+  kernel -- zombie
+  sleep
+  kernel -- sleep
+  runmem
+  kernel -- runmem
+  swap
+  sleep -- swap
+  runswap
+  swap -- runswap
+  new
+  runswap -- new
+  runswap -- runmem
+  new -- runmem
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/process.tst");
diff --git a/tst/examples/rank_same.tst b/tst/examples/rank_same.tst
index 32f7f6d..64ca18b 100644
--- a/tst/examples/rank_same.tst
+++ b/tst/examples/rank_same.tst
@@ -58,10 +58,26 @@ gap> GraphvizAddEdge(g, "X", "Y");
 <graphviz edge (X, Y)>
 
 #
-gap> AsString(g);
-"//dot\ndigraph  {\nsubgraph no_name_1 {\ngraph  [rank=\"same\"]\n\tA\n\tX\n}\
-\n\tC\nsubgraph no_name_3 {\ngraph  [rank=\"same\"]\n\tB\n\tD\n\tY\n}\n\tA -> \
-B\n\tA -> C\n\tC -> D\n\tX -> Y\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph  {
+  subgraph no_name_1 {
+    graph [rank="same"]
+    A
+    X
+  }
+  C
+  subgraph no_name_3 {
+    graph [rank="same"]
+    B
+    D
+    Y
+  }
+  A -> B
+  A -> C
+  C -> D
+  X -> Y
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/rank_same.tst");
diff --git a/tst/examples/structs.tst b/tst/examples/structs.tst
index 94eb987..5252598 100644
--- a/tst/examples/structs.tst
+++ b/tst/examples/structs.tst
@@ -63,18 +63,46 @@ gap> GraphvizAddEdge(s, "struct1:f2", "struct3:here");
 <graphviz edge (struct1:f2, struct3:here)>
 
 #
-gap> AsString(s : invalidDOT := "inappropriate addition of quotes to HTML labels FIXME");
-"//dot\ndigraph structs {\nnode  [shape=\"plaintext\"]\n\tstruct1 [label=\"<<T\
-ABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\">\n<TR>\n<TD>left</TD>\n<T\
-D PORT=\"f1\">middle</TD><TD PORT=\"f2\">right</TD>\n</TR>\n</TABLE>>\"]\n\tst\
-ruct2 [label=\"<<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\">\n<TR>\
-\n<TD PORT=\"f0\">one</TD>\n<TD>two</TD>\n</TR>\n</TABLE>>\"]\n\tstruct3 [labe\
-l=\"<<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\" CELLPADDING=\"4\">\
-\n<TR>\n<TD ROWSPAN=\"3\">hello<BR/>world</TD>\n<TD COLSPAN=\"3\">b</TD>\n<TD \
-ROWSPAN=\"3\">g</TD>\n<TD ROWSPAN=\"3\">h</TD>\n</TR>\n<TR>\n<TD>c</TD>\n<TD P\
-ORT=\"here\">d</TD>\n<TD>e</TD>\n</TR>\n<TR>\n<TD COLSPAN=\"3\">f</TD>\n</TR>\
-\n</TABLE>>\"]\n\tstruct1:f1\n\tstruct2:f0\n\tstruct1:f1 -> struct2:f0\n\tstru\
-ct1:f2\n\tstruct3:here\n\tstruct1:f2 -> struct3:here\n}\n"
+gap> Print(AsString(s : invalidDOT := "inappropriate addition of quotes to HTML labels FIXME"), "\n");
+//dot
+digraph structs {
+  node [shape="plaintext"]
+  struct1 [label="<<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+<TR>
+<TD>left</TD>
+<TD PORT="f1">middle</TD><TD PORT="f2">right</TD>
+</TR>
+</TABLE>>"]
+  struct2 [label="<<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+<TR>
+<TD PORT="f0">one</TD>
+<TD>two</TD>
+</TR>
+</TABLE>>"]
+  struct3 [label="<<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDIN\
+G="4">
+<TR>
+<TD ROWSPAN="3">hello<BR/>world</TD>
+<TD COLSPAN="3">b</TD>
+<TD ROWSPAN="3">g</TD>
+<TD ROWSPAN="3">h</TD>
+</TR>
+<TR>
+<TD>c</TD>
+<TD PORT="here">d</TD>
+<TD>e</TD>
+</TR>
+<TR>
+<TD COLSPAN="3">f</TD>
+</TR>
+</TABLE>>"]
+  struct1:f1
+  struct2:f0
+  struct1:f1 -> struct2:f0
+  struct1:f2
+  struct3:here
+  struct1:f2 -> struct3:here
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/structs.tst");
diff --git a/tst/examples/traffic_lights.tst b/tst/examples/traffic_lights.tst
index 5ad450a..31f3ba7 100644
--- a/tst/examples/traffic_lights.tst
+++ b/tst/examples/traffic_lights.tst
@@ -78,16 +78,48 @@ gap> GraphvizSetAttrs(t, rec(fontsize := "12"));
 <graphviz digraph "TrafficLights" with 14 nodes and 16 edges>
 
 #
-gap> AsString(t);
-"//dot\ndigraph TrafficLights {\ngraph  [engine=\"neato\", fontsize=\"12\", la\
-bel=\"PetriNet Model TrafficLights\nExtracted from ConceptBase and laid out by\
- Graphviz\", overlap=\"false\"]\nsubgraph ctx1 {\nnode  [shape=\"box\"]\n\tgy2\
-\n\tyr2\n\trg2\n\tgy1\n\tyr1\n\trg1\n}\nsubgraph ctx2 {\nnode  [fixedsize=\"tr\
-ue\", shape=\"circle\", width=\"0.9\"]\n\tgreen2\n\tyellow2\n\tred2\n\tsafe2\n\
-\tgreen1\n\tyellow1\n\tred1\n\tsafe1\n}\n\tgy2 -> yellow2\n\trg2 -> green2\n\t\
-yr2 -> safe1\n\tyr2 -> red2\n\tsafe2 -> rg2\n\tgreen2 -> gy2\n\tyellow2 -> yr2\
-\n\tred2 -> rg2\n\tgy1 -> yellow1\n\trg1 -> green1\n\tyr1 -> safe2\n\tyr1 -> r\
-ed1\n\tsafe1 -> rg1\n\tgreen1 -> gy1\n\tyellow1 -> yr1\n\tred1 -> rg1\n}\n"
+gap> Print(AsString(t), "\n");
+//dot
+digraph TrafficLights {
+  graph [engine="neato", fontsize="12", label="PetriNet Model TrafficLights
+Extracted from ConceptBase and laid out by Graphviz", overlap="false"]
+  subgraph ctx1 {
+    node [shape="box"]
+    gy2
+    yr2
+    rg2
+    gy1
+    yr1
+    rg1
+  }
+  subgraph ctx2 {
+    node [fixedsize="true", shape="circle", width="0.9"]
+    green2
+    yellow2
+    red2
+    safe2
+    green1
+    yellow1
+    red1
+    safe1
+  }
+  gy2 -> yellow2
+  rg2 -> green2
+  yr2 -> safe1
+  yr2 -> red2
+  safe2 -> rg2
+  green2 -> gy2
+  yellow2 -> yr2
+  red2 -> rg2
+  gy1 -> yellow1
+  rg1 -> green1
+  yr1 -> safe2
+  yr1 -> red1
+  safe1 -> rg1
+  green1 -> gy1
+  yellow1 -> yr1
+  red1 -> rg1
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/traffic_lights.tst");
diff --git a/tst/examples/unix.tst b/tst/examples/unix.tst
index 63ea0e7..9e62998 100644
--- a/tst/examples/unix.tst
+++ b/tst/examples/unix.tst
@@ -124,37 +124,7 @@ gap> GraphvizAddEdge(u, "System V.2", "System V.3");
 <graphviz edge (System V.2, System V.3)>
 
 #
-gap> AsString(u) =
-> "//dot\ndigraph unix {\nnode  [color=\"lightblue2\", size=\"6,6\", style=\"fil\
-> led\"]\n\t\"5th Edition\"\n\t\"6th Edition\"\n\t\"5th Edition\" -> \"6th Editi\
-> on\"\n\t\"PWB 1.0\"\n\t\"5th Edition\" -> \"PWB 1.0\"\n\tLSX\n\t\"6th Edition\
-> \" -> LSX\n\t\"1 BSD\"\n\t\"6th Edition\" -> \"1 BSD\"\n\t\"Mini Unix\"\n\t\"6\
-> th Edition\" -> \"Mini Unix\"\n\tWollongong\n\t\"6th Edition\" -> Wollongong\n\
-> \tInterdata\n\t\"6th Edition\" -> Interdata\n\t\"Unix/TS 3.0\"\n\t\"Unix/TS 3.\
-> 0\" -> Interdata\n\t\"PWB 2.0\"\n\tInterdata -> \"PWB 2.0\"\n\t\"7th Edition\"\
-> \n\tInterdata -> \"7th Edition\"\n\t\"8th Edition\"\n\t\"7th Edition\" -> \"8t\
-> h Edition\"\n\t\"32V\"\n\t\"7th Edition\" -> \"32V\"\n\tV7M\n\t\"7th Edition\"\
->  -> V7M\n\t\"Ultrix-11\"\n\t\"7th Edition\" -> \"Ultrix-11\"\n\tXenix\n\t\"7th\
->  Edition\" -> Xenix\n\t\"UniPlus+\"\n\t\"7th Edition\" -> \"UniPlus+\"\n\tV7M \
-> -> \"Ultrix-11\"\n\t\"9th Edition\"\n\t\"8th Edition\" -> \"9th Edition\"\n\t\
-> \"2 BSD\"\n\t\"1 BSD\" -> \"2 BSD\"\n\t\"2.8 BSD\"\n\t\"2 BSD\" -> \"2.8 BSD\"\
-> \n\t\"2.8 BSD\" -> \"Ultrix-11\"\n\t\"2.9 BSD\"\n\t\"2.8 BSD\" -> \"2.9 BSD\"\
-> \n\t\"3 BSD\"\n\t\"32V\" -> \"3 BSD\"\n\t\"4 BSD\"\n\t\"3 BSD\" -> \"4 BSD\"\n\
-> \t\"4.1 BSD\"\n\t\"4 BSD\" -> \"4.1 BSD\"\n\t\"4.2 BSD\"\n\t\"4.1 BSD\" -> \"4\
-> .2 BSD\"\n\t\"4.1 BSD\" -> \"2.8 BSD\"\n\t\"4.1 BSD\" -> \"8th Edition\"\n\t\"\
-> 4.3 BSD\"\n\t\"4.2 BSD\" -> \"4.3 BSD\"\n\t\"Ultrix-32\"\n\t\"4.2 BSD\" -> \"U\
-> ltrix-32\"\n\t\"PWB 1.2\"\n\t\"PWB 1.0\" -> \"PWB 1.2\"\n\t\"USG 1.0\"\n\t\"PW\
-> B 1.0\" -> \"USG 1.0\"\n\t\"PWB 1.2\" -> \"PWB 2.0\"\n\t\"CB Unix 1\"\n\t\"USG\
->  1.0\" -> \"CB Unix 1\"\n\t\"USG 2.0\"\n\t\"USG 1.0\" -> \"USG 2.0\"\n\t\"CB U\
-> nix 2\"\n\t\"CB Unix 1\" -> \"CB Unix 2\"\n\t\"CB Unix 3\"\n\t\"CB Unix 2\" ->\
->  \"CB Unix 3\"\n\t\"Unix/TS++\"\n\t\"CB Unix 3\" -> \"Unix/TS++\"\n\t\"PDP-11 \
-> Sys V\"\n\t\"CB Unix 3\" -> \"PDP-11 Sys V\"\n\t\"USG 3.0\"\n\t\"USG 2.0\" -> \
-> \"USG 3.0\"\n\t\"USG 3.0\" -> \"Unix/TS 3.0\"\n\t\"PWB 2.0\" -> \"Unix/TS 3.0\
-> \"\n\t\"Unix/TS 1.0\"\n\t\"Unix/TS 1.0\" -> \"Unix/TS 3.0\"\n\t\"TS 4.0\"\n\t\
-> \"Unix/TS 3.0\" -> \"TS 4.0\"\n\t\"Unix/TS++\" -> \"TS 4.0\"\n\t\"CB Unix 3\" \
-> -> \"TS 4.0\"\n\t\"System V.0\"\n\t\"TS 4.0\" -> \"System V.0\"\n\t\"System V.\
-> 2\"\n\t\"System V.0\" -> \"System V.2\"\n\t\"System V.3\"\n\t\"System V.2\" ->\
->  \"System V.3\"\n}\n";
+gap> Print(AsString(u), "\n");
 #I  invalid node name 5th Edition using "5th Edition" instead
 #I  invalid node name 6th Edition using "6th Edition" instead
 #I  invalid node name 5th Edition using "5th Edition" instead
@@ -280,7 +250,100 @@ gap> AsString(u) =
 #I  invalid node name System V.3 using "System V.3" instead
 #I  invalid node name System V.2 using "System V.2" instead
 #I  invalid node name System V.3 using "System V.3" instead
-true
+//dot
+digraph unix {
+  node [color="lightblue2", size="6,6", style="filled"]
+  "5th Edition"
+  "6th Edition"
+  "5th Edition" -> "6th Edition"
+  "PWB 1.0"
+  "5th Edition" -> "PWB 1.0"
+  LSX
+  "6th Edition" -> LSX
+  "1 BSD"
+  "6th Edition" -> "1 BSD"
+  "Mini Unix"
+  "6th Edition" -> "Mini Unix"
+  Wollongong
+  "6th Edition" -> Wollongong
+  Interdata
+  "6th Edition" -> Interdata
+  "Unix/TS 3.0"
+  "Unix/TS 3.0" -> Interdata
+  "PWB 2.0"
+  Interdata -> "PWB 2.0"
+  "7th Edition"
+  Interdata -> "7th Edition"
+  "8th Edition"
+  "7th Edition" -> "8th Edition"
+  "32V"
+  "7th Edition" -> "32V"
+  V7M
+  "7th Edition" -> V7M
+  "Ultrix-11"
+  "7th Edition" -> "Ultrix-11"
+  Xenix
+  "7th Edition" -> Xenix
+  "UniPlus+"
+  "7th Edition" -> "UniPlus+"
+  V7M -> "Ultrix-11"
+  "9th Edition"
+  "8th Edition" -> "9th Edition"
+  "2 BSD"
+  "1 BSD" -> "2 BSD"
+  "2.8 BSD"
+  "2 BSD" -> "2.8 BSD"
+  "2.8 BSD" -> "Ultrix-11"
+  "2.9 BSD"
+  "2.8 BSD" -> "2.9 BSD"
+  "3 BSD"
+  "32V" -> "3 BSD"
+  "4 BSD"
+  "3 BSD" -> "4 BSD"
+  "4.1 BSD"
+  "4 BSD" -> "4.1 BSD"
+  "4.2 BSD"
+  "4.1 BSD" -> "4.2 BSD"
+  "4.1 BSD" -> "2.8 BSD"
+  "4.1 BSD" -> "8th Edition"
+  "4.3 BSD"
+  "4.2 BSD" -> "4.3 BSD"
+  "Ultrix-32"
+  "4.2 BSD" -> "Ultrix-32"
+  "PWB 1.2"
+  "PWB 1.0" -> "PWB 1.2"
+  "USG 1.0"
+  "PWB 1.0" -> "USG 1.0"
+  "PWB 1.2" -> "PWB 2.0"
+  "CB Unix 1"
+  "USG 1.0" -> "CB Unix 1"
+  "USG 2.0"
+  "USG 1.0" -> "USG 2.0"
+  "CB Unix 2"
+  "CB Unix 1" -> "CB Unix 2"
+  "CB Unix 3"
+  "CB Unix 2" -> "CB Unix 3"
+  "Unix/TS++"
+  "CB Unix 3" -> "Unix/TS++"
+  "PDP-11 Sys V"
+  "CB Unix 3" -> "PDP-11 Sys V"
+  "USG 3.0"
+  "USG 2.0" -> "USG 3.0"
+  "USG 3.0" -> "Unix/TS 3.0"
+  "PWB 2.0" -> "Unix/TS 3.0"
+  "Unix/TS 1.0"
+  "Unix/TS 1.0" -> "Unix/TS 3.0"
+  "TS 4.0"
+  "Unix/TS 3.0" -> "TS 4.0"
+  "Unix/TS++" -> "TS 4.0"
+  "CB Unix 3" -> "TS 4.0"
+  "System V.0"
+  "TS 4.0" -> "System V.0"
+  "System V.2"
+  "System V.0" -> "System V.2"
+  "System V.3"
+  "System V.2" -> "System V.3"
+}
 
 #
 gap> STOP_TEST("graphviz package: examples/unix.tst");
diff --git a/tst/graph.tst b/tst/graph.tst
index 6eba0ac..c5b70de 100644
--- a/tst/graph.tst
+++ b/tst/graph.tst
@@ -179,8 +179,11 @@ rec( edge := rec(  ), graph := rec( color := "red" ), node := rec(  ) )
 gap> g := GraphvizGraph();;
 gap> GraphvizSetAttr(g, "color", "red");;
 gap> GraphvizSetAttr(g, "color", "blue");;
-gap> AsString(g);
-"//dot\ngraph  {\ngraph  [color=\"blue\"]\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  graph [color="blue"]
+}
 
 # # Test removing attributes from a graph TODO uncomment or delete
 # gap> g := GraphvizGraph();;
diff --git a/tst/node.tst b/tst/node.tst
index 3d9b9d3..89e6235 100644
--- a/tst/node.tst
+++ b/tst/node.tst
@@ -54,15 +54,21 @@ rec( shape := "circle" )
 # Test name containing ':'
 gap> g := GraphvizGraph();;
 gap> GraphvizAddNode(g, "test:colon");;
-gap> AsString(g);
-"//dot\ngraph  {\n\ttest:colon\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  test:colon
+}
 
 # Test non-string name containing ':'
 gap> g := GraphvizGraph();;
 gap> n := GraphvizAddNode(g, 111);
 <graphviz node "111">
-gap> AsString(g);
-"//dot\ngraph  {\n\t111\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  111
+}
 gap> GraphvizGetAttr(n, 1);
 fail
 gap> GraphvizSetAttr(n, 1, 2);
diff --git a/tst/subgraph.tst b/tst/subgraph.tst
index ba19045..8182137 100644
--- a/tst/subgraph.tst
+++ b/tst/subgraph.tst
@@ -149,9 +149,18 @@ gap> GraphvizAddEdge(g, "x", "y");;
 gap> GraphvizSetAttr(s, "color", "red");;
 gap> GraphvizSetAttrs(s, rec(node := rec(color := "red")));;
 gap> GraphvizSetAttrs(s, rec(edge := rec(color := "red")));;
-gap> AsString(g);
-"//dot\ndigraph  {\nsubgraph a {\ngraph  [color=\"red\"]\nnode  [color=\"red\"\
-]\nedge  [color=\"red\"]\n}\n\tx\n\ty\n\tx -> y\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph  {
+  subgraph a {
+    graph [color="red"]
+    node [color="red"]
+    edge [color="red"]
+  }
+  x
+  y
+  x -> y
+}
 
 # Test stringifying subgraph graph
 gap> g := GraphvizGraph();;
@@ -160,9 +169,18 @@ gap> GraphvizAddEdge(g, "x", "y");;
 gap> GraphvizSetAttr(s, "color", "red");;
 gap> GraphvizSetAttrs(s, rec(node := rec(color := "red")));;
 gap> GraphvizSetAttrs(s, rec(edge := rec(color := "red")));;
-gap> AsString(g);
-"//dot\ngraph  {\nsubgraph a {\ngraph  [color=\"red\"]\nnode  [color=\"red\"]\
-\nedge  [color=\"red\"]\n}\n\tx\n\ty\n\tx -- y\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  subgraph a {
+    graph [color="red"]
+    node [color="red"]
+    edge [color="red"]
+  }
+  x
+  y
+  x -- y
+}
 
 # Test stringifying subgraph context (graph)
 gap> g := GraphvizGraph();;
@@ -171,9 +189,19 @@ gap> GraphvizAddEdge(g, "x", "y");;
 gap> GraphvizSetAttr(s, "color", "red");;
 gap> GraphvizSetAttrs(s, rec(node := rec(color := "red")));;
 gap> GraphvizSetAttrs(s, rec(edge := rec(color := "red")));;
-gap> AsString(g);
-"//dot\ngraph  {\n// a context \n{\ngraph  [color=\"red\"]\nnode  [color=\"red\
-\"]\nedge  [color=\"red\"]\n}\n\tx\n\ty\n\tx -- y\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  {
+    // context "a" 
+    graph [color="red"]
+    node [color="red"]
+    edge [color="red"]
+  }
+  x
+  y
+  x -- y
+}
 
 # Test stringifying subgraph context (digraph)
 gap> g := GraphvizDigraph();;
@@ -182,15 +210,29 @@ gap> GraphvizAddEdge(g, "x", "y");;
 gap> GraphvizSetAttr(s, "color", "red");;
 gap> GraphvizSetAttrs(s, rec(node := rec(color := "red")));;
 gap> GraphvizSetAttrs(s, rec(edge := rec(color := "red")));;
-gap> AsString(g);
-"//dot\ndigraph  {\n// a context \n{\ngraph  [color=\"red\"]\nnode  [color=\"r\
-ed\"]\nedge  [color=\"red\"]\n}\n\tx\n\ty\n\tx -> y\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph  {
+  {
+    // context "a" 
+    graph [color="red"]
+    node [color="red"]
+    edge [color="red"]
+  }
+  x
+  y
+  x -> y
+}
 
 # Test stringifying subgraph w/o name
 gap> g := GraphvizDigraph();;
 gap> s := GraphvizAddSubgraph(g);;
-gap> AsString(g);
-"//dot\ndigraph  {\nsubgraph no_name_1 {\n}\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph  {
+  subgraph no_name_1 {
+  }
+}
 
 # finding a node in a sibling graph
 gap> g := GraphvizDigraph();;
@@ -258,10 +300,18 @@ gap> GraphvizSetAttrs(g, rec(node := rec(color := "blue"),
 > edge := rec(label := "testing123", color := "blue")));;
 gap> GraphvizSetAttrs(ctx, rec(node := rec(color := "red")));;
 gap> GraphvizAddNode(ctx, "a");;
-gap> AsString(g);
-"//dot\ndigraph  {\ngraph  [color=\"green\"]\nnode  [color=\"blue\"]\nedge  [c\
-olor=\"blue\", label=\"testing123\"]\n// no_name_1 context \n{\nnode  [color=\
-\"red\"]\n\ta\n}\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph  {
+  graph [color="green"]
+  node [color="blue"]
+  edge [color="blue", label="testing123"]
+  {
+    // context "no_name_1" 
+    node [color="red"]
+    a
+  }
+}
 
 # Test adding subgraphs with the same name
 gap> g := GraphvizDigraph();;
@@ -307,8 +357,14 @@ gap> GraphvizSubgraphs(s1).c;
 gap> g := GraphvizGraph();;
 gap> s1 := GraphvizAddSubgraph(g, "a");;
 gap> s2 := GraphvizAddSubgraph(s1, "c");;
-gap> AsString(g);
-"//dot\ngraph  {\nsubgraph a {\nsubgraph c {\n}\n}\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph  {
+  subgraph a {
+    subgraph c {
+    }
+  }
+}
 
 # Test subgraphs with non-string names
 gap> g := GraphvizGraph();;
@@ -379,18 +435,38 @@ gap> g      := GraphvizGraph("g");;
 gap> parent := GraphvizAddContext(g, "parent");;
 gap> ctx    := GraphvizAddContext(parent, "ctx");;
 gap> GraphvizAddEdge(ctx, "a", "b");;
-gap> AsString(g);
-"//dot\ngraph g {\n// parent context \n{\n// ctx context \n{\n\ta\n\tb\n\ta --\
- b\n}\n}\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+graph g {
+  {
+    // context "parent" 
+    {
+      // context "ctx" 
+      a
+      b
+      a -- b
+    }
+  }
+}
 
 # Test nested contexts have correct edge types (digraph)
 gap> g      := GraphvizDigraph("g");;
 gap> parent := GraphvizAddContext(g, "parent");;
 gap> ctx    := GraphvizAddContext(parent, "ctx");;
 gap> GraphvizAddEdge(ctx, "a", "b");;
-gap> AsString(g);
-"//dot\ndigraph g {\n// parent context \n{\n// ctx context \n{\n\ta\n\tb\n\ta \
--> b\n}\n}\n}\n"
+gap> Print(AsString(g), "\n");
+//dot
+digraph g {
+  {
+    // context "parent" 
+    {
+      // context "ctx" 
+      a
+      b
+      a -> b
+    }
+  }
+}
 
 # Test finding subgraph (non-string name)
 gap> g := GraphvizGraph("r");;
@@ -410,9 +486,17 @@ gap> GraphvizSetAttrs(legend, rec(node := rec(shape := "plaintext")));
 <graphviz context "legend" with 0 nodes and 0 edges>
 gap> GraphvizAddSubgraph(legend, "legend");
 <graphviz graph "legend" with 0 nodes and 0 edges>
-gap> AsString(gv);
-"//dot\ngraph context_and_subgraph {\nnode  [shape=\"box\"]\n// legend context\
- \n{\nnode  [shape=\"plaintext\"]\nsubgraph legend {\n}\n}\n}\n"
+gap> Print(AsString(gv), "\n");
+//dot
+graph context_and_subgraph {
+  node [shape="box"]
+  {
+    // context "legend" 
+    node [shape="plaintext"]
+    subgraph legend {
+    }
+  }
+}
 
 # Test a context containing a subdigraph
 gap> gv := GraphvizDigraph("context+subgraph");;