[instrumentation_adapter] Update documentation about using androidx (#2028)

* Update documentation about how to use androidx.
* Increase patch version.
* Fix change log.

packages/instrumentation_adapter/CHANGELOG.md

diff --git a/packages/instrumentation_adapter/CHANGELOG.md b/packages/instrumentation_adapter/CHANGELOG.md
index ace51df..73557c5 100644
--- a/packages/instrumentation_adapter/CHANGELOG.md
+++ b/packages/instrumentation_adapter/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.1.1
+
+* Updates about using *androidx* library.
+
 ## 0.1.0
 
 * Update boilerplate test to use `@Rule` instead of `FlutterTest`.

packages/instrumentation_adapter/README.md

diff --git a/packages/instrumentation_adapter/README.md b/packages/instrumentation_adapter/README.md
index 49a3395..81f5155 100644
--- a/packages/instrumentation_adapter/README.md
+++ b/packages/instrumentation_adapter/README.md
@@ -1,14 +1,18 @@
 # instrumentation_adapter
 
-Adapts flutter_test results as Android instrumentation tests, making them usable for Firebase Test Lab and other Android CI providers.
+Adapts flutter_test results as Android instrumentation tests, making them usable
+for Firebase Test Lab and other Android CI providers.
 
 iOS support is not available yet, but is planned in the future.
 
 ## Usage
 
-Add a dependency on the `instrumentation_adapter` package in the `dev_dependencies` section of pubspec.yaml. For plugins, do this in the pubspec.yaml of the example app.
+Add a dependency on the `instrumentation_adapter` package in the
+`dev_dependencies` section of pubspec.yaml. For plugins, do this in the
+pubspec.yaml of the example app.
 
-Invoke `InstrumentationAdapterFlutterBinding.ensureInitialized()` at the start of a test file.
+Invoke `InstrumentationAdapterFlutterBinding.ensureInitialized()` at the start
+of a test file.
 
 ```dart
 import 'package:instrumentation_adapter/instrumentation_adapter.dart';
@@ -23,10 +27,9 @@
 ```
 
 Create an instrumentation test file in your application's
-android/app/src/androidTest/java/com/example/myapp/ directory
-(replacing com, example, and myapp with values from your app's
-package name). You can name this test file MainActivityTest.java
-or another name of your choice.
+**android/app/src/androidTest/java/com/example/myapp/** directory (replacing
+com, example, and myapp with values from your app's package name). You can name
+this test file MainActivityTest.java or another name of your choice.
 
 ```
 package com.example.myapp;
@@ -43,6 +46,28 @@
 }
 ```
 
+Update your application's **myapp/android/app/build.gradle** to make sure it
+uses androidx's version of AndroidJUnitRunner and has androidx libraries as a
+dependency.
+
+```
+android {
+  ...
+  defaultConfig {
+    ...
+    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+  }
+}
+
+dependencies {
+    testImplementation 'junit:junit:4.12'
+
+    // https://developer.android.com/jetpack/androidx/releases/test/#1.2.0
+    androidTestImplementation 'androidx.test:runner:1.2.0'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+}
+```
+
 Use gradle commands to build an instrumentation test for Android.
 
 ```
@@ -52,7 +77,8 @@
 popd
 ```
 
-Upload to Firebase Test Lab, making sure to replace <PATH_TO_KEY_FILE>, <PROJECT_NAME>, <RESULTS_BUCKET>, and <RESULTS_DIRECTORY> with your values.
+Upload to Firebase Test Lab, making sure to replace <PATH_TO_KEY_FILE>,
+<PROJECT_NAME>, <RESULTS_BUCKET>, and <RESULTS_DIRECTORY> with your values.
 
 ```
 gcloud auth activate-service-account --key-file=<PATH_TO_KEY_FILE>

packages/instrumentation_adapter/android/build.gradle

diff --git a/packages/instrumentation_adapter/android/build.gradle b/packages/instrumentation_adapter/android/build.gradle
index a117873..21c4213 100644
--- a/packages/instrumentation_adapter/android/build.gradle
+++ b/packages/instrumentation_adapter/android/build.gradle
@@ -26,16 +26,17 @@
 
     defaultConfig {
         minSdkVersion 16
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
     lintOptions {
         disable 'InvalidPackage'
     }
     dependencies {
         api 'junit:junit:4.12'
-        api 'androidx.test:core:1.0.0'
-        api 'androidx.test:runner:1.1.1'
-        api 'androidx.test:rules:1.1.1'
-        api 'androidx.test.espresso:espresso-core:3.1.1'
+
+        // https://developer.android.com/jetpack/androidx/releases/test/#1.2.0
+        api 'androidx.test:runner:1.2.0'
+        api 'androidx.test:rules:1.2.0'
+        api 'androidx.test.espresso:espresso-core:3.2.0'
     }
 }

packages/instrumentation_adapter/pubspec.yaml

diff --git a/packages/instrumentation_adapter/pubspec.yaml b/packages/instrumentation_adapter/pubspec.yaml
index 0d67157..b73c749 100644
--- a/packages/instrumentation_adapter/pubspec.yaml
+++ b/packages/instrumentation_adapter/pubspec.yaml
@@ -1,6 +1,6 @@
 name: instrumentation_adapter
 description: Runs tests that use the flutter_test API as platform native instrumentation tests.
-version: 0.1.0
+version: 0.1.1
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/instrumentation_adapter