Ensure Android tests compile and fix warnings

.buildkite/pipeline.yml

@@ -4,7 +4,7 @@
 # We propagate the environment to the container (sse https://github.com/buildkite-plugins/docker-buildkite-plugin#propagate-environment-optional-boolean)
 
 steps:
-  - label: "Unit test"
+  - label: "Compile and run Unit tests"
     agents:
       # We use a medium sized instance instead of the normal small ones because
       # gradle build is long
@@ -16,6 +16,18 @@ steps:
           image: "runmymind/docker-android-sdk"
           propagate-environment: true
 
+  - label: "Compile Android tests"
+    agents:
+      # We use a medium sized instance instead of the normal small ones because
+      # gradle build is long
+      queue: "medium"
+    commands:
+      - "./gradlew clean assembleAndroidTest --stacktrace"
+    plugins:
+      - docker#v3.1.0:
+          image: "runmymind/docker-android-sdk"
+          propagate-environment: true
+
   - label: "Assemble GPlay Debug version"
     agents:
       # We use a medium sized instance instead of the normal small ones because

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/InstrumentedTest.kt

@@ -17,12 +17,12 @@
 package im.vector.matrix.android
 
 import android.content.Context
-import androidx.test.InstrumentationRegistry
+import androidx.test.core.app.ApplicationProvider
 import java.io.File
 
 interface InstrumentedTest {
     fun context(): Context {
-        return InstrumentationRegistry.getTargetContext()
+        return ApplicationProvider.getApplicationContext()
     }
 
     fun cacheDir(): File {

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/auth/AuthenticatorTest.kt

@@ -17,8 +17,8 @@
 package im.vector.matrix.android.auth
 
 import androidx.test.annotation.UiThreadTest
+import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.rule.GrantPermissionRule
-import androidx.test.runner.AndroidJUnit4
 import im.vector.matrix.android.InstrumentedTest
 import im.vector.matrix.android.OkReplayRuleChainNoActivity
 import im.vector.matrix.android.api.auth.Authenticator