[android] expose offline database merge API

platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/offline/OfflineManagerTest.kt

@@ -0,0 +1,119 @@
+package com.mapbox.mapboxsdk.testapp.offline
+
+import android.R
+import android.content.Context
+import android.support.test.espresso.Espresso.onView
+import android.support.test.espresso.IdlingRegistry
+import android.support.test.espresso.UiController
+import android.support.test.espresso.assertion.ViewAssertions.matches
+import android.support.test.espresso.idling.CountingIdlingResource
+import android.support.test.espresso.matcher.ViewMatchers.isDisplayed
+import android.support.test.espresso.matcher.ViewMatchers.withId
+import android.support.test.runner.AndroidJUnit4
+import com.mapbox.mapboxsdk.maps.MapboxMap
+import com.mapbox.mapboxsdk.offline.OfflineManager
+import com.mapbox.mapboxsdk.offline.OfflineRegion
+import com.mapbox.mapboxsdk.testapp.action.MapboxMapAction.invoke
+import com.mapbox.mapboxsdk.testapp.activity.BaseActivityTest
+import com.mapbox.mapboxsdk.testapp.activity.espresso.EspressoTestActivity
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.io.File
+import java.io.FileOutputStream
+
+@RunWith(AndroidJUnit4::class)
+class OfflineManagerTest : BaseActivityTest() {
+
+  companion object {
+    private const val TEST_DB_FILE_NAME = "offline.db"
+  }
+
+  private val context: Context by lazy { rule.activity }
+
+  private lateinit var offlineIdlingResource: CountingIdlingResource
+
+  override fun getActivityClass(): Class<*> {
+    return EspressoTestActivity::class.java
+  }
+
+  override fun beforeTest() {
+    super.beforeTest()
+    offlineIdlingResource = CountingIdlingResource("idling_resource")
+    IdlingRegistry.getInstance().register(offlineIdlingResource)
+  }
+
+  @Test
+  fun offlineMergeListDeleteTest() {
+    validateTestSetup()
+
+    invoke(mapboxMap) { _: UiController, _: MapboxMap ->
+      offlineIdlingResource.increment()
+      copyAsset(context)
+      OfflineManager.getInstance(context).mergeOfflineRegions(
+        context.filesDir.absolutePath + "/" + TEST_DB_FILE_NAME,
+        object : OfflineManager.MergeOfflineRegionsCallback {
+          override fun onMerge(offlineRegions: Array<out OfflineRegion>?) {
+            assert(offlineRegions?.size == 1)
+            offlineIdlingResource.decrement()
+          }
+
+          override fun onError(error: String?) {
+            throw RuntimeException("Unable to merge external offline database. $error")
+          }
+        })
+    }
+
+    invoke(mapboxMap) { _: UiController, _: MapboxMap ->
+      offlineIdlingResource.increment()
+      OfflineManager.getInstance(context).listOfflineRegions(object : OfflineManager.ListOfflineRegionsCallback {
+        override fun onList(offlineRegions: Array<out OfflineRegion>?) {
+          assert(offlineRegions?.size == 1)
+          if (offlineRegions != null) {
+            for (region in offlineRegions) {
+              offlineIdlingResource.increment()
+              region.delete(object : OfflineRegion.OfflineRegionDeleteCallback {
+                override fun onDelete() {
+                  offlineIdlingResource.decrement()
+                }
+
+                override fun onError(error: String?) {
+                  throw RuntimeException("Unable to delete region with ID: ${region.id}. $error")
+                }
+              })
+            }
+          } else {
+            throw RuntimeException("Unable to find merged region.")
+          }
+          offlineIdlingResource.decrement()
+        }
+
+        override fun onError(error: String?) {
+          throw RuntimeException("Unable to obtain offline regions list. $error")
+        }
+      })
+    }
+
+    // waiting for offline idling resource
+    onView(withId(R.id.content)).check(matches(isDisplayed()))
+  }
+
+  override fun afterTest() {
+    super.afterTest()
+    IdlingRegistry.getInstance().unregister(offlineIdlingResource)
+  }
+
+  private fun copyAsset(context: Context) {
+    val bufferSize = 1024
+    val assetManager = context.assets
+    val inputStream = assetManager.open(TEST_DB_FILE_NAME)
+    val outputStream = FileOutputStream(File(context.filesDir.absoluteFile, TEST_DB_FILE_NAME))
+
+    try {
+      inputStream.copyTo(outputStream, bufferSize)
+    } finally {
+      inputStream.close()
+      outputStream.flush()
+      outputStream.close()
+    }
+  }
+}