diff --git a/content/media/test/Makefile.in b/content/media/test/Makefile.in
index d19837cd6a7e..b584c6759da5 100644
--- a/content/media/test/Makefile.in
+++ b/content/media/test/Makefile.in
@@ -343,6 +343,9 @@ ifdef MOZ_DASH
 MOCHITEST_FILES += \
     test_can_play_type_dash.html \
     dash/dash-manifest.mpd \
+    dash/dash-manifest-sjs.mpd \
+    test_dash_detect_stream_switch.html \
+    dash_detect_stream_switch.sjs \
     dash/dash-webm-video-320x180.webm \
     dash/dash-webm-video-428x240.webm \
     dash/dash-webm-audio-128k.webm \
diff --git a/content/media/test/dash/dash-manifest-sjs.mpd b/content/media/test/dash/dash-manifest-sjs.mpd
new file mode 100644
index 000000000000..c7ecba3c692d
--- /dev/null
+++ b/content/media/test/dash/dash-manifest-sjs.mpd
@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<MPD
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xmlns="urn:mpeg:DASH:schema:MPD:2011"
+  xsi:schemaLocation="urn:mpeg:DASH:schema:MPD:2011"
+  type="static"
+  mediaPresentationDuration="PT3.958S"
+  minBufferTime="PT1S"
+  profiles="urn:webm:dash:profile:webm-on-demand:2012">
+  <BaseURL>./dash_detect_stream_switch.sjs?name=</BaseURL>
+  <Period id="0" start="PT0S" duration="PT3.958S" >
+    <AdaptationSet id="0" mimeType="video/webm" codecs="vp8" lang="eng" subsegmentAlignment="true" subsegmentStartsWithSAP="1" bitstreamSwitching="true">
+      <Representation id="0" bandwidth="54207" width="320" height="180">
+        <BaseURL>dash-webm-video-320x180.webm</BaseURL>
+        <SegmentBase indexRange="35090-35123">
+          <Initialization range="0-228" />
+        </SegmentBase>
+      </Representation>
+      <Representation id="1" bandwidth="78006" width="428" height="240">
+        <BaseURL>dash-webm-video-428x240.webm</BaseURL>
+        <SegmentBase indexRange="50173-50206">
+          <Initialization range="0-228" />
+        </SegmentBase>
+      </Representation>
+    </AdaptationSet>
+    <AdaptationSet id="1" mimeType="audio/webm" codecs="vorbis" lang="eng" audioSamplingRate="48000" subsegmentStartsWithSAP="1">
+      <Representation id="2" bandwidth="57264">
+        <BaseURL>dash-webm-audio-128k.webm</BaseURL>
+        <SegmentBase indexRange="41927-41946">
+          <Initialization range="0-4521" />
+        </SegmentBase>
+      </Representation>
+    </AdaptationSet>
+  </Period>
+</MPD>
diff --git a/content/media/test/dash_detect_stream_switch.sjs b/content/media/test/dash_detect_stream_switch.sjs
new file mode 100644
index 000000000000..3ceecf9c7eac
--- /dev/null
+++ b/content/media/test/dash_detect_stream_switch.sjs
@@ -0,0 +1,114 @@
+/* -*- Mode: JavaScript; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* dash_detect_stream_switch.sjs
+ *
+ * Parses requests for DASH manifests and ensures stream switching takes place
+ * by verifying the subsegments downloaded and the streams they belong to.
+ * If unexpected subsegments (byte ranges) are requested, the script will
+ * will respond with a 404.
+ */
+
+var DEBUG = false;
+
+function parseQuery(request, key) {
+  var params = request.queryString.split('&');
+  if (DEBUG) {
+    dump("DASH-SJS: request params = \"" + params + "\"\n");
+  }
+  for (var j = 0; j < params.length; ++j) {
+    var p = params[j];
+	if (p == key)
+	  return true;
+    if (p.indexOf(key + "=") === 0)
+	  return p.substring(key.length + 1);
+	if (p.indexOf("=") < 0 && key === "")
+	  return p;
+  }
+  return false;
+}
+
+function handleRequest(request, response)
+{
+  try {
+    var name = parseQuery(request, "name");
+    var range = request.hasHeader("Range") ? request.getHeader("Range")
+                                           : undefined;
+    
+    // Should not get request for 1st subsegment from 2nd stream, nor 2nd
+    // subsegment from 1st stream.
+    if (name == "dash-webm-video-320x180.webm" && range == "bytes=25514-32767" ||
+        name == "dash-webm-video-428x240.webm" && range == "bytes=228-35852") 
+    {
+      throw "Should not request " + name + " with byte-range " + range;
+    } else {
+      var rangeSplit = range.split("=");
+      if (rangeSplit.length != 2) {
+        throw "DASH-SJS: ERROR: invalid number of tokens (" + rangeSplit.length +
+              ") delimited by \'=\' in \'Range\' header.";
+      }
+      var offsets = rangeSplit[1].split("-");
+      if (offsets.length != 2) {
+        throw "DASH-SJS: ERROR: invalid number of tokens (" + offsets.length +
+              ") delimited by \'-\' in \'Range\' header.";
+      }
+      var startOffset = parseInt(offsets[0]);
+      var endOffset = parseInt(offsets[1]);
+      var file = Components.classes["@mozilla.org/file/directory_service;1"].
+                            getService(Components.interfaces.nsIProperties).
+                            get("CurWorkD", Components.interfaces.nsILocalFile);
+      var fis  = Components.classes['@mozilla.org/network/file-input-stream;1'].
+                            createInstance(Components.interfaces.nsIFileInputStream);
+      var bis  = Components.classes["@mozilla.org/binaryinputstream;1"].
+                            createInstance(Components.interfaces.nsIBinaryInputStream);
+
+      var paths = "tests/content/media/test/" + name;
+      var split = paths.split("/");
+      for (var i = 0; i < split.length; ++i) {
+        file.append(split[i]);
+      }
+
+      fis.init(file, -1, -1, false);
+      // Exception: start offset should be within file bounds.
+      if (startOffset > file.fileSize) {
+        throw "Starting offset [" + startOffset + "] is after end of file [" +
+              file.fileSize + "].";
+      }
+      // End offset may be too large in the MPD. Real world HTTP servers just
+      // return what data they can; do the same here - reduce the end offset.
+      if (endOffset >= file.fileSize) {
+        if (DEBUG) {
+          dump("DASH-SJS: reducing endOffset [" + endOffset + "] to fileSize [" +
+               (file.fileSize-1) + "]\n");
+        }
+        endOffset = file.fileSize-1;
+      }
+      fis.seek(Components.interfaces.nsISeekableStream.NS_SEEK_SET, startOffset);
+      bis.setInputStream(fis);
+      
+      var byteLengthToRead = endOffset + 1 - startOffset;
+      var totalBytesExpected = byteLengthToRead + startOffset;
+      if (DEBUG) {
+        dump("DASH-SJS: byteLengthToRead = " + byteLengthToRead +
+             " byteLengthToRead+startOffset = " + totalBytesExpected +
+             " fileSize = " + file.fileSize + "\n");
+      }
+
+      var bytes = bis.readBytes(byteLengthToRead);
+      response.setStatusLine(request.httpVersion, 206, "Partial Content");
+      response.setHeader("Content-Length", ""+bytes.length, false);
+      response.setHeader("Content-Type", "application/dash+xml", false);
+      var contentRange = "bytes " + startOffset + "-" + endOffset + "/" +
+                         file.fileSize;
+      response.setHeader("Content-Range", contentRange, false);
+      response.write(bytes, bytes.length);
+      bis.close();
+    }
+  } catch (e) {
+    dump ("DASH-SJS-ERROR: " + e + "\n");
+    response.setStatusLine(request.httpVersion, 404, "Not found");
+  }
+}
diff --git a/content/media/test/manifest.js b/content/media/test/manifest.js
index c662b5ad4610..2513049b45fd 100644
--- a/content/media/test/manifest.js
+++ b/content/media/test/manifest.js
@@ -195,6 +195,13 @@ var gInvalidTests = [
   { name:"invalid-cmap-s1c2.opus", type:"audio/ogg; codecs=opus"},
 ];
 
+// Files to test for stream switching. Note: media files referenced in DASH MPD
+// files should be accessed via dash_detect_stream_switch.sjs.
+var gStreamSwitchTests = [
+  { name:"dash-manifest-sjs.mpd", type:"application/dash+xml",
+    width:320, height:180, duration:3.966 }
+];
+
 // Converts a path/filename to a file:// URI which we can load from disk.
 // Optionally checks whether the file actually exists on disk at the location
 // we've specified.
diff --git a/content/media/test/test_dash_detect_stream_switch.html b/content/media/test/test_dash_detect_stream_switch.html
new file mode 100644
index 000000000000..cc7152a2a2b1
--- /dev/null
+++ b/content/media/test/test_dash_detect_stream_switch.html
@@ -0,0 +1,81 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=792935
+-->
+<head>
+  <title>Test for Bug 792935 - DASH Stream Switching</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript" src="manifest.js"></script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=792935">Mozilla Bug 792935</a>
+  
+</div>
+<pre id="test">
+<script type="text/javascript">
+
+var manager = new MediaTestManager;
+
+function createTestArray() {
+  var tests = [];
+  var tmpVid = document.createElement("video");
+
+  for (var testNum=0; testNum<gStreamSwitchTests.length; testNum++) {
+    var test = gStreamSwitchTests[testNum];
+    if (!tmpVid.canPlayType(test.type)) {
+      continue;
+    }
+    tests.push(test);
+  }
+  return tests;
+}
+
+function ended(evt) {
+  var v = evt.target;
+  if (v.parentNode) {
+    v.parentNode.removeChild(v);
+  }
+  ok(true, "Fully played DASH video implies correct byte ranges downloaded.");
+  dump("STREAM-SWITCH-TEST: Finished " + v._name + "\n");
+  manager.finished(v.token);
+}
+
+function error(evt) {
+  var v = evt.target;
+  ok(false, "Error suggests wrong byte range requested for " + v._name);
+}
+
+function startTest(test, token) {
+  var v = document.createElement('video');
+  manager.started(token);
+  v.type = test.type;
+  v.src = test.name;
+  v._name = test.name + " stream switch test";
+  v.token = token;
+  v.autoplay = true;
+
+  v.addEventListener("error", error, false);
+  v.addEventListener("ended", ended, false);
+
+  dump("STREAM-SWITCH-TEST: Started " + name + "\n");
+  document.body.appendChild(v);
+}
+
+var testArray = createTestArray();
+if (testArray && testArray.length > 0) {
+  manager.runTests(testArray, startTest);
+} else {
+  var v = document.createElement('video');
+  var canPlay = v.canPlayType("application/dash+xml");
+  // If the test array is empty even though DASH is enabled, the test should
+  // fail, i.e. canPlay should be false when testArray is empty.
+  todo(canPlay, "No types supported - DASH " +
+                (canPlay ? "enabled" : "disabled"));
+}  
+
+</script>
+</pre>
+</body>
+</html>