[DOC] Runnable docstring examples and doctest coverage for core constructors

[FrancescAlted]

Following issue #650 (which added runnable examples to CTable.where() and sort_by()), several fundamental array constructors in src/blosc2/ndarray.py (empty, zeros, full, fromiter, asarray, linspace) and core SChunk methods in src/blosc2/schunk.py (append_data, get_chunk, decompress_chunk) lack runnable, copy-pasteable Examples: sections in their docstrings.

Furthermore, pytest.ini currently tests doctests only on core.py, ndarray.py, and schunk.py.

Suggested Work

1. Add NumPy-style runnable docstrings with code and expected output to:
   • src/blosc2/ndarray.py: empty(), zeros(), full(), fromiter(), asarray(), linspace().
   • src/blosc2/schunk.py: append_data(), get_chunk(), decompress_chunk().
   • src/blosc2/lazyexpr.py: compute(), save().
2. Demonstrate realistic parameters in each example: chunks=, blocks=, cparams=, and urlpath=.
3. Verify that all docstrings pass pytest --doctest-modules.

[HughStanway]

Hi, I can take a look at this. Thanks!

[HughStanway]

Hi, a quick question to check I am going in the right direction - I can see most of these functions already have Examples: sections in their docstrings. It does look like some of them only over the basic usage so is the goal here to extend and improve the scenarios where they already exist?

[FrancescAlted]

Yeah, the idea is to make sure that examples are easily understandable, and that most (ideally all, but not always possible/desirable) public methods/functions have the Examples section filled in. Making them more complete by using different params (like chunks=, blocks=, cparams=, and urlpath=) in different examples is also a good way to make the user more familiar with the possibilities. This requires some manual playing, and reflection on what are the good parameters to show.