Nobody's trying to fool you by not including sales taxes. There's just no way to show them in advance, unless you want to start typing your address and zip code into every shopping website before you even browse.
I've never been through the "regular" IT hiring process myself, but I've interviewed several candidates for an Android developer position. I liked asking questions and looking at how the person thinks. I didn't expect exact correct answers for every question, I just wanted to see whether they have a fundamental understanding of Android. After that, they had to build a small app at home (not my initiative) to show their skills.
There are better questions where I do think google should be allowed but they aren't LC-style. Some examples are building APIs or operating on files