diff --git a/src/v3/core/graph.test.js b/src/v3/core/graph.test.js
index edf95b4..56371dd 100644
--- a/src/v3/core/graph.test.js
+++ b/src/v3/core/graph.test.js
@@ -16,6 +16,7 @@ import {
   edgeToString,
   edgeToParts,
 } from "./graph";
+import {advancedGraph} from "./graphTestUtil";
 
 describe("core/graph", () => {
   function _unused_itExportsDistinctNodeAddressAndEdgeAddressTypes() {
@@ -34,105 +35,6 @@ describe("core/graph", () => {
     });
   });
 
-  function advancedGraph() {
-    // The advanced graph has the following features:
-    // - Multiple edges of same hom, from `src` to `dst`
-    // - An isolated node, `isolated`
-    // - A loop
-    // - A node and edge with the same toParts representation
-    // This function exposes all of the pieces of the advanced graph.
-    // It also returns two different versions of the graph, which are
-    // logically equivalent but very different history
-    // To avoid contamination, every piece is exposed as a function
-    // which generates a clean copy of that piece.
-    const src = () => NodeAddress.fromParts(["src"]);
-    const dst = () => NodeAddress.fromParts(["dst"]);
-    const hom1 = () => ({
-      src: src(),
-      dst: dst(),
-      address: EdgeAddress.fromParts(["hom", "1"]),
-    });
-    const hom2 = () => ({
-      src: src(),
-      dst: dst(),
-      address: EdgeAddress.fromParts(["hom", "2"]),
-    });
-    const loop = () => NodeAddress.fromParts(["loop"]);
-    const loop_loop = () => ({
-      src: loop(),
-      dst: loop(),
-      address: EdgeAddress.fromParts(["loop"]),
-    });
-    const isolated = () => NodeAddress.fromParts(["isolated"]);
-    const graph1 = () =>
-      new Graph()
-        .addNode(src())
-        .addNode(dst())
-        .addNode(loop())
-        .addNode(isolated())
-        .addEdge(hom1())
-        .addEdge(hom2())
-        .addEdge(loop_loop());
-
-    // graph2 is logically equivalent to graph1, but is constructed with very
-    // different history.
-    // Use this to check that logically equivalent graphs are treated
-    // equivalently, regardless of their history.
-    const phantomNode = () => NodeAddress.fromParts(["phantom"]);
-    const phantomEdge1 = () => ({
-      src: src(),
-      dst: phantomNode(),
-      address: EdgeAddress.fromParts(["phantom"]),
-    });
-    const phantomEdge2 = () => ({
-      src: src(),
-      dst: isolated(),
-      address: EdgeAddress.fromParts(["not", "so", "isolated"]),
-    });
-    // To verify that the graphs are equivalent, every mutation is preceded
-    // by a comment stating what the set of nodes and edges are prior to that mutation
-    const graph2 = () =>
-      new Graph()
-        // N: [], E: []
-        .addNode(phantomNode())
-        // N: [phantomNode], E: []
-        .addNode(src())
-        // N: [phantomNode, src], E: []
-        .addEdge(phantomEdge1())
-        // N: [phantomNode, src], E: [phantomEdge1]
-        .addNode(isolated())
-        // N: [phantomNode, src, isolated], E: [phantomEdge1]
-        .removeEdge(phantomEdge1().address)
-        // N: [phantomNode, src, isolated], E: []
-        .addNode(dst())
-        // N: [phantomNode, src, isolated, dst], E: []
-        .addEdge(hom1())
-        // N: [phantomNode, src, isolated, dst], E: [hom1]
-        .addEdge(phantomEdge2())
-        // N: [phantomNode, src, isolated, dst], E: [hom1, phantomEdge2]
-        .addEdge(hom2())
-        // N: [phantomNode, src, isolated, dst], E: [hom1, phantomEdge2, hom2]
-        .removeEdge(hom1().address)
-        // N: [phantomNode, src, isolated, dst], E: [phantomEdge2, hom2]
-        .removeNode(phantomNode())
-        // N: [src, isolated, dst], E: [phantomEdge2, hom2]
-        .removeEdge(phantomEdge2().address)
-        // N: [src, isolated, dst], E: [hom2]
-        .removeNode(isolated())
-        // N: [src, dst], E: [hom2]
-        .addNode(isolated())
-        // N: [src, dst, isolated], E: [hom2]
-        .addNode(loop())
-        // N: [src, dst, isolated, loop], E: [hom2]
-        .addEdge(loop_loop())
-        // N: [src, dst, isolated, loop], E: [hom2, loop_loop]
-        .addEdge(hom1());
-    // N: [src, dst, isolated, loop], E: [hom2, loop_loop, hom1]
-    const nodes = {src, dst, loop, isolated, phantomNode};
-    const edges = {hom1, hom2, loop_loop, phantomEdge1, phantomEdge2};
-    return {nodes, edges, graph1, graph2};
-  }
-
   describe("Graph class", () => {
     it("can be constructed", () => {
       const x = new Graph();
diff --git a/src/v3/core/graphTestUtil.js b/src/v3/core/graphTestUtil.js
new file mode 100644
index 0000000..d7929f9
--- /dev/null
+++ b/src/v3/core/graphTestUtil.js
@@ -0,0 +1,102 @@
+// @flow
+
+import {EdgeAddress, Graph, NodeAddress} from "./graph";
+
+export function advancedGraph() {
+  // The advanced graph has the following features:
+  // - Multiple edges of same hom, from `src` to `dst`
+  // - An isolated node, `isolated`
+  // - A loop
+  // - A node and edge with the same toParts representation
+  // This function exposes all of the pieces of the advanced graph.
+  // It also returns two different versions of the graph, which are
+  // logically equivalent but very different history
+  // To avoid contamination, every piece is exposed as a function
+  // which generates a clean copy of that piece.
+  const src = () => NodeAddress.fromParts(["src"]);
+  const dst = () => NodeAddress.fromParts(["dst"]);
+  const hom1 = () => ({
+    src: src(),
+    dst: dst(),
+    address: EdgeAddress.fromParts(["hom", "1"]),
+  });
+  const hom2 = () => ({
+    src: src(),
+    dst: dst(),
+    address: EdgeAddress.fromParts(["hom", "2"]),
+  });
+  const loop = () => NodeAddress.fromParts(["loop"]);
+  const loop_loop = () => ({
+    src: loop(),
+    dst: loop(),
+    address: EdgeAddress.fromParts(["loop"]),
+  });
+  const isolated = () => NodeAddress.fromParts(["isolated"]);
+  const graph1 = () =>
+    new Graph()
+      .addNode(src())
+      .addNode(dst())
+      .addNode(loop())
+      .addNode(isolated())
+      .addEdge(hom1())
+      .addEdge(hom2())
+      .addEdge(loop_loop());
+
+  // graph2 is logically equivalent to graph1, but is constructed with very
+  // different history.
+  // Use this to check that logically equivalent graphs are treated
+  // equivalently, regardless of their history.
+  const phantomNode = () => NodeAddress.fromParts(["phantom"]);
+  const phantomEdge1 = () => ({
+    src: src(),
+    dst: phantomNode(),
+    address: EdgeAddress.fromParts(["phantom"]),
+  });
+  const phantomEdge2 = () => ({
+    src: src(),
+    dst: isolated(),
+    address: EdgeAddress.fromParts(["not", "so", "isolated"]),
+  });
+  // To verify that the graphs are equivalent, every mutation is preceded
+  // by a comment stating what the set of nodes and edges are prior to that mutation
+  const graph2 = () =>
+    new Graph()
+      // N: [], E: []
+      .addNode(phantomNode())
+      // N: [phantomNode], E: []
+      .addNode(src())
+      // N: [phantomNode, src], E: []
+      .addEdge(phantomEdge1())
+      // N: [phantomNode, src], E: [phantomEdge1]
+      .addNode(isolated())
+      // N: [phantomNode, src, isolated], E: [phantomEdge1]
+      .removeEdge(phantomEdge1().address)
+      // N: [phantomNode, src, isolated], E: []
+      .addNode(dst())
+      // N: [phantomNode, src, isolated, dst], E: []
+      .addEdge(hom1())
+      // N: [phantomNode, src, isolated, dst], E: [hom1]
+      .addEdge(phantomEdge2())
+      // N: [phantomNode, src, isolated, dst], E: [hom1, phantomEdge2]
+      .addEdge(hom2())
+      // N: [phantomNode, src, isolated, dst], E: [hom1, phantomEdge2, hom2]
+      .removeEdge(hom1().address)
+      // N: [phantomNode, src, isolated, dst], E: [phantomEdge2, hom2]
+      .removeNode(phantomNode())
+      // N: [src, isolated, dst], E: [phantomEdge2, hom2]
+      .removeEdge(phantomEdge2().address)
+      // N: [src, isolated, dst], E: [hom2]
+      .removeNode(isolated())
+      // N: [src, dst], E: [hom2]
+      .addNode(isolated())
+      // N: [src, dst, isolated], E: [hom2]
+      .addNode(loop())
+      // N: [src, dst, isolated, loop], E: [hom2]
+      .addEdge(loop_loop())
+      // N: [src, dst, isolated, loop], E: [hom2, loop_loop]
+      .addEdge(hom1());
+  // N: [src, dst, isolated, loop], E: [hom2, loop_loop, hom1]
+  const nodes = {src, dst, loop, isolated, phantomNode};
+  const edges = {hom1, hom2, loop_loop, phantomEdge1, phantomEdge2};
+  return {nodes, edges, graph1, graph2};
+}