diff -r 000000000000 -r 6474c204b198 mobile/android/base/tests/testJarReader.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/tests/testJarReader.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,52 @@
+package org.mozilla.gecko.tests;
+
+import java.io.InputStream;
+
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.util.GeckoJarReader;
+
+/**
+ * A basic jar reader test. Tests reading a png from fennec's apk, as well
+ * as loading some invalid jar urls.
+ */
+public class testJarReader extends BaseTest {
+    public void testJarReader() {
+        String appPath = getActivity().getApplication().getPackageResourcePath();
+        mAsserter.isnot(appPath, null, "getPackageResourcePath is non-null");
+
+        // Test reading a file from a jar url that looks correct.
+        String url = "jar:file://" + appPath + "!/" + AppConstants.OMNIJAR_NAME;
+        InputStream stream = GeckoJarReader.getStream("jar:" + url + "!/chrome/chrome/content/branding/favicon32.png");
+        mAsserter.isnot(stream, null, "JarReader returned non-null for valid file in valid jar");
+
+        // Test looking for an non-existent file in a jar.
+        url = "jar:file://" + appPath + "!/" + AppConstants.OMNIJAR_NAME;
+        stream = GeckoJarReader.getStream("jar:" + url + "!/chrome/chrome/content/branding/nonexistent_file.png");
+        mAsserter.is(stream, null, "JarReader returned null for non-existent file in valid jar");
+
+        // Test looking for a file that doesn't exist in the APK.
+        url = "jar:file://" + appPath + "!/" + "BAD" + AppConstants.OMNIJAR_NAME;
+        stream = GeckoJarReader.getStream("jar:" + url + "!/chrome/chrome/content/branding/favicon32.png");
+        mAsserter.is(stream, null, "JarReader returned null for valid file in invalid jar file");
+
+        // Test looking for an jar with an invalid url.
+        url = "jar:file://" + appPath + "!" + "!/" + AppConstants.OMNIJAR_NAME;
+        stream = GeckoJarReader.getStream("jar:" + url + "!/chrome/chrome/content/branding/nonexistent_file.png");
+        mAsserter.is(stream, null, "JarReader returned null for bad jar url");
+
+        // Test looking for a file that doesn't exist on disk.
+        url = "jar:file://" + appPath + "BAD" + "!/" + AppConstants.OMNIJAR_NAME;
+        stream = GeckoJarReader.getStream("jar:" + url + "!/chrome/chrome/content/branding/favicon32.png");
+        mAsserter.is(stream, null, "JarReader returned null for a non-existent APK");
+
+        // This test completes very quickly. If it completes too soon, the
+        // minidumps directory may not be created before the process is
+        // taken down, causing bug 722166.
+        blockForGeckoReady();
+    }
+
+    private String getData(InputStream stream) {
+        return new java.util.Scanner(stream).useDelimiter("\\A").next();
+    }
+
+}