@Test
public void testDropColumnWhenColumnNameIsNull() throws Exception {

    SQLException sqlException = new SQLException();
    when(connectionMock.prepareStatement(contains("DROP COLUMN null"))).thenReturn(preparedStatementMock);
    when(preparedStatementMock.executeUpdate()).thenThrow(sqlException);
    Connection conn = connectionMock;
    String tableName = "tableName";
    String columnName = null;
    dao.dropColumn(conn, tableName, columnName);
    verify(connectionMock, times(1)).prepareStatement(anyString());
    verify(preparedStatementMock, times(1)).executeUpdate();
    verify(preparedStatementMock, times(1)).close();
    verify(loggerMock, times(0)).debug(anyString());
    verify(loggerMock, times(1)).warn(anyString(), eq(sqlException));
}