TF-2953 Set up Patrol tests

android/app/build.gradle

@@ -23,7 +23,7 @@ if (flutterVersionName == null) {
 
 def flutterMinSdkVersion = localProperties.getProperty('flutter.minSdkVersion')
 if (flutterMinSdkVersion == null) {
-    flutterMinSdkVersion = '19'
+    flutterMinSdkVersion = '21'
 }
 
 apply plugin: 'com.android.application'
@@ -54,6 +54,8 @@ android {
         manifestPlaceholders = [
                 'appAuthRedirectScheme': 'teammail.mobile'
         ]
+        testInstrumentationRunner "pl.leancode.patrol.PatrolJUnitRunner"
+        testInstrumentationRunnerArguments clearPackageData: "true"
     }
 
     compileOptions {
@@ -77,7 +79,15 @@ android {
             // Signing with the debug keys for now, so `flutter run --release` works.
             signingConfig signingConfigs.release
         }
+        debug {
+            minifyEnabled false
+        }
     }
+
+    testOptions {
+        execution "ANDROIDX_TEST_ORCHESTRATOR"
+    }
+
 }
 
 flutter {
@@ -90,4 +100,5 @@ dependencies {
     implementation 'androidx.work:work-runtime-ktx:2.7.0'
     implementation 'com.android.support:multidex:1.0.3'
     implementation 'androidx.window:window:1.0.0'
+    androidTestUtil "androidx.test:orchestrator:1.5.0"
 }

android/app/src/androidTest/java/com/linagora/android/tmail/MainActivityTest.java

@@ -0,0 +1,33 @@
+package com.linagora.android.tmail;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+import pl.leancode.patrol.PatrolJUnitRunner;
+
+@RunWith(Parameterized.class)
+public class MainActivityTest {
+    @Parameters(name = "{0}")
+    public static Object[] testCases() {
+        PatrolJUnitRunner instrumentation = (PatrolJUnitRunner) InstrumentationRegistry.getInstrumentation();
+        // replace "MainActivity.class" with "io.flutter.embedding.android.FlutterActivity.class" 
+        // if your AndroidManifest is using: android:name="io.flutter.embedding.android.FlutterActivity"
+        instrumentation.setUp(MainActivity.class);
+        instrumentation.waitForPatrolAppService();
+        return instrumentation.listDartTests();
+    }
+
+    public MainActivityTest(String dartTestName) {
+        this.dartTestName = dartTestName;
+    }
+
+    private final String dartTestName;
+
+    @Test
+    public void runDartTest() {
+        PatrolJUnitRunner instrumentation = (PatrolJUnitRunner) InstrumentationRegistry.getInstrumentation();
+        instrumentation.runDartTest(dartTestName);
+    }
+}