diff --git a/api/server/src/test/dataset/graph.edges.csv b/api/server/src/test/dataset/graph.edges.csv
index 654d462..9e6ef6b 100644
--- a/api/server/src/test/dataset/graph.edges.csv
+++ b/api/server/src/test/dataset/graph.edges.csv
@@ -1,9 +1,22 @@
-swh:1:dir:0000000000000000000000000000000000000001 swh:1:dir:0000000000000000000000000000000000000002
-swh:1:dir:0000000000000000000000000000000000000002 swh:1:dir:0000000000000000000000000000000000000003
-swh:1:dir:0000000000000000000000000000000000000002 swh:1:dir:0000000000000000000000000000000000000005
-swh:1:dir:0000000000000000000000000000000000000001 swh:1:dir:0000000000000000000000000000000000000008
-swh:1:dir:0000000000000000000000000000000000000003 swh:1:cnt:0000000000000000000000000000000000000004
-swh:1:dir:0000000000000000000000000000000000000005 swh:1:cnt:0000000000000000000000000000000000000006
-swh:1:dir:0000000000000000000000000000000000000002 swh:1:cnt:0000000000000000000000000000000000000007
-swh:1:dir:0000000000000000000000000000000000000008 swh:1:cnt:0000000000000000000000000000000000000009
-swh:1:dir:0000000000000000000000000000000000000001 swh:1:cnt:0000000000000000000000000000000000000010
+swh:1:dir:0000000000000000000000000000000000000002 swh:1:cnt:0000000000000000000000000000000000000001
+swh:1:rev:0000000000000000000000000000000000000003 swh:1:dir:0000000000000000000000000000000000000002
+swh:1:dir:0000000000000000000000000000000000000008 swh:1:cnt:0000000000000000000000000000000000000001
+swh:1:dir:0000000000000000000000000000000000000008 swh:1:dir:0000000000000000000000000000000000000006
+swh:1:dir:0000000000000000000000000000000000000006 swh:1:cnt:0000000000000000000000000000000000000004
+swh:1:dir:0000000000000000000000000000000000000006 swh:1:cnt:0000000000000000000000000000000000000005
+swh:1:dir:0000000000000000000000000000000000000008 swh:1:cnt:0000000000000000000000000000000000000007
+swh:1:rev:0000000000000000000000000000000000000009 swh:1:dir:0000000000000000000000000000000000000008
+swh:1:rel:0000000000000000000000000000000000000010 swh:1:rev:0000000000000000000000000000000000000009
+swh:1:rev:0000000000000000000000000000000000000009 swh:1:rev:0000000000000000000000000000000000000003
+swh:1:dir:0000000000000000000000000000000000000012 swh:1:cnt:0000000000000000000000000000000000000011
+swh:1:dir:0000000000000000000000000000000000000012 swh:1:dir:0000000000000000000000000000000000000008
+swh:1:rev:0000000000000000000000000000000000000013 swh:1:dir:0000000000000000000000000000000000000012
+swh:1:rev:0000000000000000000000000000000000000013 swh:1:rev:0000000000000000000000000000000000000009
+swh:1:dir:0000000000000000000000000000000000000017 swh:1:cnt:0000000000000000000000000000000000000014
+swh:1:dir:0000000000000000000000000000000000000017 swh:1:dir:0000000000000000000000000000000000000016
+swh:1:dir:0000000000000000000000000000000000000016 swh:1:cnt:0000000000000000000000000000000000000015
+swh:1:rev:0000000000000000000000000000000000000018 swh:1:dir:0000000000000000000000000000000000000017
+swh:1:rev:0000000000000000000000000000000000000018 swh:1:rev:0000000000000000000000000000000000000013
+swh:1:rel:0000000000000000000000000000000000000019 swh:1:rev:0000000000000000000000000000000000000018
+swh:1:snp:0000000000000000000000000000000000000020 swh:1:rev:0000000000000000000000000000000000000009
+swh:1:snp:0000000000000000000000000000000000000020 swh:1:rel:0000000000000000000000000000000000000010
diff --git a/api/server/src/test/dataset/img/.gitignore b/api/server/src/test/dataset/img/.gitignore
new file mode 100644
index 0000000..e33609d
--- /dev/null
+++ b/api/server/src/test/dataset/img/.gitignore
@@ -0,0 +1 @@
+*.png
diff --git a/api/server/src/test/dataset/img/Makefile b/api/server/src/test/dataset/img/Makefile
new file mode 100644
index 0000000..dffebbd
--- /dev/null
+++ b/api/server/src/test/dataset/img/Makefile
@@ -0,0 +1,9 @@
+all: graph.png
+
+%.png: %.dot
+	dot -Gdpi=300 -Tpng $< -o $@
+
+.PHONY: clean
+
+clean:
+	rm graph.png
diff --git a/api/server/src/test/dataset/img/graph.dot b/api/server/src/test/dataset/img/graph.dot
new file mode 100644
index 0000000..80460a7
--- /dev/null
+++ b/api/server/src/test/dataset/img/graph.dot
@@ -0,0 +1,74 @@
+digraph "Software Heritage mini DAG" {
+    ranksep=1;
+    nodesep=0.5;
+
+    subgraph cnt {
+        01 [label="cnt:0x01"];
+        04 [label="cnt:0x04"];
+        05 [label="cnt:0x05"];
+        07 [label="cnt:0x07"];
+        11 [label="cnt:0x11"];
+        14 [label="cnt:0x14"];
+        15 [label="cnt:0x15"];
+    }
+
+    subgraph cluster_dir {
+        label="File contents";
+        node [shape=folder];
+        02 [label="dir:0x02"];
+        06 [label="dir:0x06"];
+        08 [label="dir:0x08"];
+        12 [label="dir:0x12"];
+        16 [label="dir:0x16"];
+        17 [label="dir:0x17"];
+
+        02 -> 01;
+        06 -> 04;
+        06 -> 05;
+        08 -> 01;
+        08 -> 06;
+        08 -> 07;
+        12 -> 08;
+        12 -> 11;
+        16 -> 15;
+        17 -> 14;
+        17 -> 16;
+    }
+
+    subgraph cluster_rev {
+        label="Revisions";
+        node [shape=diamond];
+        03 [label="rev:0x03"];
+        09 [label="rev:0x09"];
+        13 [label="rev:0x13"];
+        18 [label="rev:0x18"];
+
+        03 -> 02;
+        09 -> 08;
+        13 -> 12;
+        18 -> 17;
+        // horizontal rev -> rev edges
+        09 -> 03 [constraint=false];
+        13 -> 09 [constraint=false];
+        18 -> 13 [constraint=false];
+    }
+
+    subgraph cluster_rel {
+        label="Releases";
+        node [shape=octagon];
+        10 [label="rel:0x10"];
+        19 [label="rel:0x19"];
+
+        10 -> 09;
+        19 -> 18;
+    }
+
+    subgraph cluster_snp {
+        label="Snapshots";
+        node [shape=doubleoctagon];
+        20 [label="snp:0x20"];
+
+        20 -> 09;
+        20 -> 10;
+    }
+}