[map] expose getter for the view used for rendering OpenGL on (#87)

MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/maps/RenderViewGetterTest.kt

@@ -0,0 +1,51 @@
+package com.mapbox.mapboxsdk.testapp.maps
+
+import android.opengl.GLSurfaceView
+import android.support.test.annotation.UiThreadTest
+import android.support.test.rule.ActivityTestRule
+import android.support.test.runner.AndroidJUnit4
+import android.view.TextureView
+import android.view.ViewGroup
+import com.mapbox.mapboxsdk.AppCenter
+import com.mapbox.mapboxsdk.maps.MapView
+import com.mapbox.mapboxsdk.maps.MapboxMapOptions
+import com.mapbox.mapboxsdk.testapp.activity.FeatureOverviewActivity
+import java.util.concurrent.CountDownLatch
+import junit.framework.Assert.assertNotNull
+import junit.framework.Assert.assertTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class RenderViewGetterTest : AppCenter() {
+
+  @Rule
+  @JvmField
+  var rule = ActivityTestRule(FeatureOverviewActivity::class.java)
+
+  private lateinit var rootView: ViewGroup
+  private lateinit var mapView: MapView
+  private val latch: CountDownLatch = CountDownLatch(1)
+
+  @Test
+  @UiThreadTest
+  fun testGLSurfaceView() {
+    rootView = rule.activity.findViewById(android.R.id.content)
+    mapView = MapView(rule.activity)
+    assertNotNull(mapView.renderView)
+    assertTrue(mapView.renderView is GLSurfaceView)
+  }
+
+  @Test
+  @UiThreadTest
+  fun testTextureView() {
+    rootView = rule.activity.findViewById(android.R.id.content)
+    mapView = MapView(rule.activity,
+      MapboxMapOptions.createFromAttributes(rule.activity, null)
+        .textureMode(true)
+    )
+    assertNotNull(mapView.renderView)
+    assertTrue(mapView.renderView is TextureView)
+  }
+}