[TeseCase] unify the getResourcesString

Bug: 173099559
Test: atest PreferredNetworkModePreferenceControllerTest  (PASS)
atest OpenNetworkSelectPagePreferenceControllerTest (PASS)
atest MobilePlanPreferenceControllerTest            (PASS)
atest MobileDataPreferenceControllerTest            (PASS)
atest Enhanced4gLteSliceHelperTest                  (PASS)
atest AutoSelectPreferenceControllerTest            (PASS)

Change-Id: I9a2e3d69cbd933a1282d51b7d8869e6a1ec4cb14

tests/unit/src/com/android/settings/testutils/ResourcesUtils.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.settings.testutils;
+
+import android.content.Context;
+
+public final class ResourcesUtils {
+    public static int getResourcesId(Context context, String type, String name) {
+        return context.getResources().getIdentifier(name, type, context.getPackageName());
+    }
+
+    public static String getResourcesString(Context context, String name) {
+        return context.getResources().getString(getResourcesId(context, "string", name));
+    }
+
+    public static String getResourcesString(Context context, String name, Object value) {
+        return context.getResources().getString(getResourcesId(context, "string", name), value);
+    }
+}