Path_exists() function

[heavelock]

Hey!
So here is promised PR for path_exists().
I also added tests for dirs and files, should I also add tests for hard/soft links? And sorry for their general clumsiness, I'm writing rust basically for the first time and I still have to wrap my head around it.

Closes: #1102

[casey]

Hey! So here is promised PR for path_exists(). I also added tests for dirs and files, should I also add tests for hard/soft links?

Since we're using Path::exists, which is provided to us, we don't need fully comprehensive tests. In general, I think it's safe to assume that you're dependencies are correct, especially when it comes from the standard library. So for this, I think we can just have one test when a file exists, and another when it doesn't.

And sorry for their general clumsiness, I'm writing rust basically for the first time and I still have to wrap my head around it.

No worries, rust is hard, and the way just runs tests is ideosyncratic!

[heavelock]

Thanks for your comments! I applied your suggestions and removed the tests for directories since we don't necessarily need to test for them.

Should I somehow refer in docs that this function is using internally rust's std behaviour?

[casey]

I think it probably isn't necessary to reference the stdlib function. I looked at the documentation for Path::exists, and we could probably include some of the details. I also think it's probably a good idea to put the function under a more descriptive heading, maybe, so something like:

#### Filesystem Access

- `path_exists(path)` - Returns `true` if the path points at an existing entity and `false` otherwise. Traverses symbolic links, and returns `false` if the path is inaccessible or points to a broken symlink.

[heavelock]

I changed the readme entry according to your suggestion.

[casey]

Nice, merged! Thank you for the PR! I think there are probably a lot of other useful boolean functions that can be added now.