diff -r 000000000000 -r 6474c204b198 testing/mozbase/mozdevice/tests/sut_fileExists.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing/mozbase/mozdevice/tests/sut_fileExists.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,29 @@
+from sut import MockAgent
+import mozdevice
+import unittest
+
+class FileExistsTest(unittest.TestCase):
+
+    commands = [('isdir /', 'TRUE'),
+                ('cd /', ''),
+                ('ls', 'init')]
+
+    def test_onRoot(self):
+        root_commands = [('isdir /', 'TRUE')]
+        a = MockAgent(self, commands=root_commands)
+        d = mozdevice.DroidSUT("127.0.0.1", port=a.port)
+        self.assertTrue(d.fileExists('/'))
+
+    def test_onNonexistent(self):
+        a = MockAgent(self, commands=self.commands)
+        d = mozdevice.DroidSUT("127.0.0.1", port=a.port)
+        self.assertFalse(d.fileExists('/doesNotExist'))
+
+    def test_onRegularFile(self):
+        a = MockAgent(self, commands=self.commands)
+        d = mozdevice.DroidSUT("127.0.0.1", port=a.port)
+        self.assertTrue(d.fileExists('/init'))
+
+if __name__ == '__main__':
+    unittest.main()
+