Test: parcel marshalling for user credentials page

Unit test to verify that the internal Credential that gets passed to
dialogs for removing said credential is actually a valid Parcelable
object, since it's hard to provoke a marshal/unmarshal in real-world
usage (but not impossible).

Bug: 22541933
Change-Id: I780ca2d7b01fc6081b9ea8b2810cfc97f0433a86

src/com/android/settings/UserCredentialsSettings.java

@@ -194,8 +194,8 @@ public class UserCredentialsSettings extends InstrumentedFragment implements OnI
         }
     }
 
-    private static class Credential implements Parcelable {
+    static class Credential implements Parcelable {
-        private static enum Type {
+        static enum Type {
             CA_CERTIFICATE (Credentials.CA_CERTIFICATE),
             USER_CERTIFICATE (Credentials.USER_CERTIFICATE),
             USER_PRIVATE_KEY (Credentials.USER_PRIVATE_KEY),

tests/src/com/android/settings/UserCredentialsTests.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2016 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;
+
+import android.os.Parcel;
+import android.test.InstrumentationTestCase;
+import android.test.InstrumentationTestRunner;
+import android.test.suitebuilder.annotation.LargeTest;
+
+import static com.android.settings.UserCredentialsSettings.Credential;
+
+/**
+ * User credentials settings fragment tests
+ *
+ * To run the test, use command:
+ * adb shell am instrument -e class com.android.settings.security.UserCredentialsTests
+ * -w com.android.settings.tests/android.test.InstrumentationTestRunner
+ *
+ */
+public class UserCredentialsTests extends InstrumentationTestCase {
+    private static final String TAG = "UserCredentialsTests";
+
+    public void testCredentialIsParcelable() {
+        final String alias = "credential-test-alias";
+        Credential c = new Credential(alias);
+
+        c.storedTypes.add(Credential.Type.CA_CERTIFICATE);
+        c.storedTypes.add(Credential.Type.USER_SECRET_KEY);
+
+        Parcel p = Parcel.obtain();
+        c.writeToParcel(p, /* flags */ 0);
+        p.setDataPosition(0);
+
+        Credential r = Credential.CREATOR.createFromParcel(p);
+        assertEquals(c.alias, r.alias);
+        assertEquals(c.storedTypes, r.storedTypes);
+    }
+}