private void getNamespacePermissionsAndVerify(String namespaceRegexWithoutPrefix,
    int expectedAmount, String expectedNamespace) throws HBaseException {
    try {
      List<UserPermission> namespacePermissions = AccessControlClient.getUserPermissions(
        systemUserConnection, PermissionStorage.toNamespaceEntry(namespaceRegexWithoutPrefix));
      assertTrue(namespacePermissions != null);
      assertEquals(expectedAmount, namespacePermissions.size());
      for (UserPermission namespacePermission : namespacePermissions) {
        // Verify it is not a global user permission
        assertFalse(namespacePermission.getAccessScope() == Permission.Scope.GLOBAL);
        // Verify namespace is set
        NamespacePermission nsPerm = (NamespacePermission) namespacePermission.getPermission();
        assertEquals(expectedNamespace, nsPerm.getNamespace());
      }
    } catch (Throwable thw) {
      throw new HBaseException(thw);
    }
  }
List all user permissions match the given regular expression for namespace and verify each of
them.
@param namespaceRegexWithoutPrefix the regualar expression for namespace, without
                                   NAMESPACE_PREFIX
@param expectedAmount              the expected amount of user permissions returned
@param expectedNamespace           the expected namespace of each user permission returned
@throws HBaseException in the case of any HBase exception when accessing hbase:acl table
hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestAccessController.java