Dealing with apostrophes and quotes

I am trying to dynamically display/hide text based on whether a given variable is passed into the shortcode. I have the shortcode set up, a php if statement wrapping the variable to test whether it has content and it works… except if the content within the variable has a quote or an apostrophe. I get: Parse error: syntax error, unexpected ‘t’ (T_STRING). I understand the error but am wondering if there is anything that allows us to pre-process that variable text before it is eval’d.

i.e. the php code

if ('{test}') {
echo '<p>My pre-wrap stuff then: {test}</p>';
}

fails with this version of the shortcode because of the apostrophe:
[demo test="Can't get this to parse."][/demo]

https://www.ads-software.com/plugins/post-snippets/