sample_updater: add non-streaming demo

SampleUpdater app was tested manually on a device.
There are unit tests for utility classes.

SampleUpdater app demonstrates how to use Android Update Engine to
apply A/B (seamless) update.
This CL contains demo of non-stream update using async update_engine,
which is accessed directly from an activity.
This app also shows logs from update_engine on the UI.
Instructions can be found in `README.md`.

- Create a UI with list of configs, current version, control buttons and a progress bar
- Add PayloadSpec and PayloadSpecs for working with update zip file
- Add UpdateConfig for working with json config files
- Add applying non-streaming update

Test: tested manually and unit tests for utilities
Change-Id: I05d4a46ad9cf8b334c9c60c7dd4da486dac0400a
Signed-off-by: Zhomart Mukhamejanov <zhomart@google.com>
diff --git a/sample_updater/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java b/sample_updater/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java
new file mode 100644
index 0000000..0101416
--- /dev/null
+++ b/sample_updater/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.systemupdatersample.ui;
+
+import static org.junit.Assert.assertNotNull;
+
+import android.support.test.filters.MediumTest;
+import android.support.test.rule.ActivityTestRule;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Make sure that the main launcher activity opens up properly, which will be
+ * verified by {@link #activityLaunches}.
+ */
+@RunWith(AndroidJUnit4.class)
+@MediumTest
+public class MainActivityTest {
+
+    @Rule
+    public final ActivityTestRule<MainActivity> mActivityRule =
+            new ActivityTestRule<>(MainActivity.class);
+
+    /**
+     * Verifies that the activity under test can be launched.
+     */
+    @Test
+    public void activityLaunches() {
+        assertNotNull(mActivityRule.getActivity());
+    }
+}