### Question:
PermissionChecker { @PermissionResult public static int checkPermission(@NonNull Context context, @NonNull String permission, int pid, int uid, @Nullable String packageName) { if (context.checkPermission(permission, pid, uid) == PackageManager.PERMISSION_DENIED) { return PERMISSION_DENIED; } String op = AppOpsManagerCompat.permissionToOp(permission); if (op == null) { return PERMISSION_GRANTED; } if (packageName == null) { String[] packageNames = context.getPackageManager().getPackagesForUid(uid); if (packageNames == null || packageNames.length <= 0) { return PERMISSION_DENIED; } packageName = packageNames[0]; } if (AppOpsManagerCompat.noteProxyOpNoThrow(context, op, packageName) != AppOpsManagerCompat.MODE_ALLOWED) { return PERMISSION_DENIED_APP_OP; } return PERMISSION_GRANTED; } private  PermissionChecker(); @PermissionResult static int checkPermission(@NonNull Context context, @NonNull String permission,
            int pid, int uid, @Nullable String packageName); @PermissionResult static int checkSelfPermission(@NonNull Context context,
            @NonNull String permission); @PermissionResult static int checkCallingPermission(@NonNull Context context,
            @NonNull String permission, @Nullable String packageName); @PermissionResult static int checkCallingOrSelfPermission(@NonNull Context context,
            @NonNull String permission); static final int PERMISSION_GRANTED; static final int PERMISSION_DENIED; static final int PERMISSION_DENIED_APP_OP; }### Answer:
@Test public void testCheckPermission() throws Exception { assertEquals(PermissionChecker.PERMISSION_DENIED, PermissionChecker.checkSelfPermission( mContext, Manifest.permission.ANSWER_PHONE_CALLS)); assertEquals(PermissionChecker.PERMISSION_GRANTED, PermissionChecker.checkSelfPermission( mContext, Manifest.permission.VIBRATE)); }