Add note about requiring an <instrumentation> tag in a test app's AndroidManifest.xml
RELNOTES: None.
@@ -170,6 +170,36 @@ The main attributes of the rule `android_instrumentation_test` are:
run the tests. See the [section on choosing an Android
device](#choosing-an-android_device) for more information.
+The test app's `AndroidManifest.xml` must include
+[an `<instrumentation>` tag](https://developer.android.com/studio/test/#configure_instrumentation_manifest_settings).
+This tag must specify the attributes for the **package of the target app** and
+the **fully qualified class name of the instrumentation test runner**,
+`android.support.test.runner.AndroidJUnitRunner`.
+
+Here is an example `AndroidTestManifest.xml` for the test app:
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+ xmlns:tools="http://schemas.android.com/tools"
+ package="com.example.android.app.test"
+ android:versionCode="1"
+ android:versionName="1.0">
+
+ <instrumentation
+ android:name="android.support.test.runner.AndroidJUnitRunner"
+ android:targetPackage="com.example.android.app" />
+
+ <uses-sdk
+ android:minSdkVersion="16"
+ android:targetSdkVersion="27" />
+
+ <application >
+ <!-- ... -->
+ </application>
+</manifest>
+```
+
## `WORKSPACE` dependencies
In order to use this rule, your project needs to depend on these external
