Fix AsyncGroup.create_dataset() dtype handling and optimize tests #3050

[dhruvak001]

Fixes https://github.com/zarr-developers/zarr-python/issues/3050

Core Fix in AsyncGroup.create_dataset():

• The issue was that when creating a dataset without providing data, the method wasn't properly handling the required dtype parameter
• Added a validation check that: -- If dtype is not provided in the arguments -- And if data is None (meaning no data is being provided to infer the dtype from) -- Then raise a clear error message saying "dtype must be provided if data is None"
• This ensures that create_array() always receives the required dtype parameter, preventing potential errors downstream

Please let me know if there is any changes needed in the issue fix.

TODO:

• [ ] Add unit tests and/or doctests in docstrings
• [ ] Add docstrings and API docs for any new/modified user-facing classes and functions
• [x] New/modified features documented in docs/user-guide/*.rst
• [x] Changes documented as a new file in changes/
• [ ] GitHub Actions have all passed
• [ ] Test coverage is 100% (Codecov passes)

[dhruvak001]

pre-commit.ci autofix

[dhruvak001]

HI @d-v-b can you please review the PR. Also do I need to make separate tests for this code changes?

[d-v-b]

i'll look at this later today

[d-v-b]

can you explain some of the changes to the hypothesis tests?

[dhruvak001]

@d-v-b When running tests locally, I was encountering issue with slow test running or test running more than the default deadline for some particular tests. I tried some changes with the fix but still it was the same. Hence I tried to avoid and optimize the test codes.

[d-v-b]

@dhruvak001 can we see what happens in our CI tests if you roll back the changes to the hypothesis tests?

[dhruvak001]

@d-v-b yup it passes even after reverting changes. Thankyou. And for the codecov patch error do i need to add a special testcase for this particular issue changes ?