read_text() of a zip file package doesn't find a resource
Hi,
In issue #44 I reported a problem with `importlib_resources.contents()` and `importlib_resources.read()`, but then the the bug title was changed, and only the first of those was fixed. Sorry if I wasn't clear enough that it wasn't just `contents()`.
The remaining problem is, `importlib_resources.read_text()` (and probably similar functions) fails to find resources in zip archives.
Here is reproducer -- run on a *nix, in an empty directory, with importlib_resources installed:
```bash
#! /bin/bash -ex
# Preparation
rm -rf demo.pyz demo
mkdir -p demo/demo
# Populate files to be packaged
echo "
import importlib_resources
def main():
for resource in importlib_resources.contents(__name__):
if resource.endswith('.txt'):
print('Reading:', resource)
text = importlib_resources.read_text(__name__, resource)
print('Length:', len(text))
" > demo/demo/__init__.py
echo "This is a resource" > demo/demo/resource.txt
# Zip everything up
python -m zipapp demo -o demo.pyz -m demo:main
# Try to run it
python --version
python demo.pyz
```
Result:
```pycon
Reading: resource.txt
Traceback (most recent call last):
File "/tmp/fghj/__venv__/lib64/python3.6/site-packages/importlib_resources/_py3.py", line 111, in open_text
full_path, mode='r', encoding=encoding, errors=errors)
NotADirectoryError: [Errno 20] Not a directory: '/tmp/demo.pyz/demo/resource.txt'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib64/python3.6/runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "/usr/lib64/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "demo.pyz/__main__.py", line 3, in <module>
File "demo.pyz/demo/__init__.py", line 8, in main
File "__venv__/lib64/python3.6/site-packages/importlib_resources/_py3.py", line 149, in read_text
with open_text(package, resource, encoding, errors) as fp:
File "__venv__/lib64/python3.6/site-packages/importlib_resources/_py3.py", line 125, in open_text
raise FileNotFoundError(message)
FileNotFoundError: 'resource.txt' resource not found in 'demo'
```
Expected result (what I get when I use `pkg_resources` by “anti-following” the Migration Guide):
```
Reading: resource.txt
Length: 19
```