diff --git a/spec/git.spec.js b/spec/git.spec.js
index 2d895370..380f8e25 100644
--- a/spec/git.spec.js
+++ b/spec/git.spec.js
@@ -14,12 +14,18 @@ var compareAnswer = function(headless, expectedJSON) {
   expect(equal).toBe(true);
 };
 
+var expectCommandToProduceTree = function(command, expectedJSON) {
+  var headless = new HeadlessGit();
+  headless.sendCommand(command);
+  compareAnswer(headless, expectedJSON);
+};
+
 describe('GitEngine', function() {
   it('Should commit off of head', function() {
-    var headless = new HeadlessGit();
-    var expectedJSON = '{"branches":{"master":{"target":"C2","id":"master","type":"branch"}},"commits":{"C0":{"type":"commit","parents":[],"id":"C0","rootCommit":true},"C1":{"type":"commit","parents":["C0"],"id":"C1"},"C2":{"type":"commit","parents":["C1"],"id":"C2"}},"HEAD":{"id":"HEAD","target":"master","type":"general ref"}}';
 
-    headless.sendCommand('git commit');
-    compareAnswer(headless, expectedJSON);
+    expectCommandToProduceTree(
+      'git commit',
+      '{"branches":{"master":{"target":"C2","id":"master","type":"branch"}},"commits":{"C0":{"type":"commit","parents":[],"id":"C0","rootCommit":true},"C1":{"type":"commit","parents":["C0"],"id":"C1"},"C2":{"type":"commit","parents":["C1"],"id":"C2"}},"HEAD":{"id":"HEAD","target":"master","type":"general ref"}}'
+    );
   });
 });