Extract magnification capabilities from MagnificationSettingsFragment into a new class.

* To increase single responsibility of MagnificationSettingsFragment

Bug: 168567356
Test: atest MagnificationCapabilitiesTest
Change-Id: Ic5e8a556858ac2b6ab9929b1bbdc373ce320c270

tests/robotests/src/com/android/settings/accessibility/MagnificationCapabilitiesTest.java

@@ -0,0 +1,59 @@
+/*
+ * 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.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settings.R;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Tests for {@link MagnificationCapabilities} */
+@RunWith(RobolectricTestRunner.class)
+public final class MagnificationCapabilitiesTest {
+
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+
+    @Test
+    public void getCapabilities_windowMode_expectedCapabilities() {
+        MagnificationCapabilities.setCapabilities(mContext,
+                MagnificationCapabilities.MagnificationMode.WINDOW);
+
+        final int windowCapabilities = MagnificationCapabilities.getCapabilities(mContext);
+        assertThat(windowCapabilities).isEqualTo(
+                MagnificationCapabilities.MagnificationMode.WINDOW);
+
+    }
+
+    @Test
+    public void getSummary_fullScreenMode_expectedSummary() {
+        final int fullScreenCapabilities = MagnificationCapabilities.MagnificationMode.FULLSCREEN;
+
+        final String actualString = MagnificationCapabilities.getSummary(mContext,
+                fullScreenCapabilities);
+
+        final String expectedString = mContext.getString(
+                R.string.accessibility_magnification_area_settings_full_screen_summary);
+        assertThat(actualString).isEqualTo(expectedString);
+    }
+}