Test commands in shell Programming

In shell programming, the test command-General Linux technology-Linux programming and kernel information is provided. The following is a detailed description. I just got started with linux and learned the shell programming if command (I have never touched programming before). there is a code on the book to view the file attributes. I don't understand it very well.
The original text is as follows:
#! /Bin/bash
# 4.10.sh
If test-z $1
Then echo 'Please input a file name'
Else
If test-w $1
Then echo "writeable"
Else
Echo "unwriteable"
Fi
If test-x $1
Then echo "excuteable"
Else
Echo "unexcuteable"
Fi
Fi
The above does not mean to output the please input a file name when the file name is not input in the test Command test.
The following should not be the writeable output when the test file cannot be written.
Is my understanding wrong? where is it?
Be considerate of the pains of self-study.