Refactored constant names to comply to the style guide; Prefixing key

for selected room with hostname to support the multi-server feature;
implemented saving the logged hostnames to prefs and it retrieval;
added the relevant tests

app/build.gradle

@@ -102,6 +102,8 @@ android {
         release {
             manifest.srcFile 'src/release/AndroidManifest.xml'
         }
+
+        test.java.srcDirs += 'src/test/kotlin'
     }
 }
 
@@ -174,6 +176,11 @@ dependencies {
     provided 'io.reactivex:rxjava:1.3.0'
     provided "com.github.akarnokd:rxjava2-interop:0.10.2"
     provided 'com.hadisatrio:Optional:v1.0.1'
+
+    testCompile 'junit:junit:4.12'
+    testCompile "org.mockito:mockito-core:2.7.19"
+    testCompile "org.jetbrains.kotlin:kotlin-test:$rootProject.ext.kotlinVersion"
+    testCompile "org.jetbrains.kotlin:kotlin-test-junit:$rootProject.ext.kotlinVersion"
 }
 
 apply plugin: 'com.google.gms.google-services'

app/src/main/java/chat/rocket/android/RocketChatCache.java

@@ -5,18 +5,29 @@ import android.content.SharedPreferences;
 
 import com.hadisatrio.optional.Optional;
 
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
 import java.util.UUID;
 
+import chat.rocket.android.log.RCLog;
 import io.reactivex.BackpressureStrategy;
 import io.reactivex.Flowable;
+import io.reactivex.annotations.NonNull;
+import io.reactivex.annotations.Nullable;
 
 /**
  * sharedpreference-based cache.
  */
 public class RocketChatCache {
-  private static final String KEY_SELECTED_SERVER_HOSTNAME = "selectedServerHostname";
-  private static final String KEY_SELECTED_ROOM_ID = "selectedRoomId";
-  private static final String KEY_PUSH_ID = "pushId";
+  private static final String KEY_SELECTED_SERVER_HOSTNAME = "KEY_SELECTED_SERVER_HOSTNAME";
+  private static final String KEY_SELECTED_ROOM_ID = "KEY_SELECTED_ROOM_ID";
+  private static final String KEY_PUSH_ID = "KEY_PUSH_ID";
+  private static final String KEY_HOSTNAME_LIST = "KEY_HOSTNAME_LIST";
 
   private Context context;
 
@@ -32,12 +43,47 @@ public class RocketChatCache {
     setString(KEY_SELECTED_SERVER_HOSTNAME, hostname);
   }
 
+  public void addHostname(@NonNull String hostname, @Nullable String hostnameAvatarUri) {
+    String hostnameList = getString(KEY_HOSTNAME_LIST, null);
+    try {
+      JSONObject json;
+      if (hostnameList == null) {
+        json = new JSONObject();
+      } else {
+        json = new JSONObject(hostnameList);
+      }
+      // Replace server avatar uri if exists.
+      json.put(hostname, hostnameAvatarUri == null ? JSONObject.NULL : hostnameAvatarUri);
+      setString(KEY_HOSTNAME_LIST, json.toString());
+    } catch (JSONException e) {
+      RCLog.e(e);
+    }
+  }
+
+  public List<String> getServerList() {
+    String json = getString(KEY_HOSTNAME_LIST, null);
+    if (json == null) {
+      return Collections.emptyList();
+    }
+    try {
+      JSONObject jsonObj = new JSONObject(json);
+      List<String> serverList = new ArrayList<>();
+      for (Iterator<String> iter = jsonObj.keys(); iter.hasNext();) {
+        serverList.add(iter.next());
+      }
+      return serverList;
+    } catch (JSONException e) {
+      RCLog.e(e);
+    }
+    return Collections.emptyList();
+  }
+
   public String getSelectedRoomId() {
-    return getString(KEY_SELECTED_ROOM_ID, null);
+    return getString(getSelectedServerHostname() + KEY_SELECTED_ROOM_ID, null);
   }
 
   public void setSelectedRoomId(String roomId) {
-    setString(KEY_SELECTED_ROOM_ID, roomId);
+    setString(getSelectedServerHostname() + KEY_SELECTED_ROOM_ID, roomId);
   }
 
   public String getOrCreatePushId() {
@@ -58,7 +104,7 @@ public class RocketChatCache {
   }
 
   public Flowable<Optional<String>> getSelectedRoomIdPublisher() {
-    return getValuePublisher(KEY_SELECTED_ROOM_ID);
+    return getValuePublisher(getSelectedServerHostname() + KEY_SELECTED_ROOM_ID);
   }
 
   private SharedPreferences getSharedPreferences() {
@@ -69,7 +115,7 @@ public class RocketChatCache {
     return getSharedPreferences().edit();
   }
 
-  private String getString(String key, String defaultValue) {
+  public String getString(String key, String defaultValue) {
     return getSharedPreferences().getString(key, defaultValue);
   }
 

app/src/test/kotlin/chat.rocket.android/RocketChatCacheTest.kt

+package chat.rocket.android;
+
+import android.content.Context
+import org.hamcrest.CoreMatchers.equalTo
+import org.json.JSONObject
+import org.junit.Assert.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.Mockito.*
+import org.mockito.junit.MockitoJUnitRunner
+
+@RunWith(MockitoJUnitRunner::class)
+class RocketChatCacheTest {
+
+    lateinit var cache: RocketChatCache
+
+    @Before
+    fun setup() {
+        val mockedContext = mock(Context::class.java)
+        val mockAppContext = mock(Context::class.java)
+        `when`(mockedContext.applicationContext).thenReturn(mockAppContext)
+        cache = spy(RocketChatCache(mockedContext))
+    }
+
+    @Test
+    fun getServerList_ShouldReturnHostnameList() {
+        val hostnameList = JSONObject()
+                .put("demo.rocket.chat", "imageuri")
+                .put("192.168.0.6:3000", "imageuri")
+                .toString()
+
+        doReturn(hostnameList).`when`(cache).getString("KEY_HOSTNAME_LIST", null)
+
+        val expectedServerList = mutableListOf("demo.rocket.chat", "192.168.0.6:3000")
+        val serverList = cache.serverList
+        expectedServerList.sort()
+        serverList.sort()
+        assertThat(cache.serverList, equalTo(expectedServerList))
+    }
+}
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