read_case: defective exception behaviour

[seanpearsonuk]

There is an existing PyFluent test, which is test_general_exception_behaviour_in_session() in test_session.py where the failing section is commented out to keep the test passing:

    # Error in server:
    # This appears to be a surface mesh.\nSurface meshes cannot be read under the /file/read-case functionality.
    # with pytest.raises(RuntimeError):
    #     solver.settings.file.read(file_type='case', file_name=mesh_file_2d)

As the comment states, there is an error in the server but there is no exception transmitted.

Following is my interactive trial:

1. Non-existent file:

>>> solver.settings.file.read_case(file_name="no_such_file.cas.h5")
...
RuntimeError: File "no_such_file.cas.h5" not found!
Error Object: #f

It's good that we get a RuntimeError here with the message 'File "no_such_file.cas.h5" not found!'. Note however that the subsequent line 'Error Object: #f' is also part of the exception message, which should not be included (in my opinion).

2. Surface mesh file:

>>> solver.settings.file.read_case(file_name=r"TaskObject3.msh.h5")
>>>

passes without incident, resulting in no exception being transmitted, but there is an error message hidden from PyFluent in the Fluent console:

Error: This appears to be a surface mesh.\nSurface meshes cannot be read under the /file/read-case functionality.
Error Object: #f

An exception should be transmitted.

3. Corrupt file:
Here we just create a pseudo-case file with some random text inside and then try to load it:

>>> solver.settings.file.read_case(file_name="nonsense.cas.h5")
>>>

Similar to the surface mesh file, we get no exception in PyFluent. Fluent, meanwhile, is making a lot of noise:

HDF5-DIAG: Error detected in HDF5 (1.12.2) MPI-process 0:
  #000: H5F.c line 620 in H5Fopen(): unable to open file
    major: File accessibility
    minor: Unable to open file
  #001: H5VLcallback.c line 3502 in H5VL_file_open(): failed to iterate over available VOL connector plugins
    major: Virtual Object Layer
    minor: Iteration failed
  #002: H5PLpath.c line 579 in H5PL__path_table_iterate(): can't iterate over plugins in plugin path '(null)'
    major: Plugin for dynamically loaded library
    minor: Iteration failed
  #003: H5PLpath.c line 713 in H5PL__path_table_iterate_process_path(): can't open directory
    major: Plugin for dynamically loaded library
    minor: Can't open directory or file
  #004: H5VLcallback.c line 3351 in H5VL__file_open(): open failed
    major: Virtual Object Layer
    minor: Can't open object
  #005: H5VLnative_file.c line 97 in H5VL__native_file_open(): unable to open file
    major: File accessibility
    minor: Unable to open file
  #006: H5Fint.c line 1990 in H5F_open(): unable to read superblock
    major: File accessibility
    minor: Read failed
  #007: H5Fsuper.c line 405 in H5F__super_read(): file signature not found
    major: File accessibility
    minor: Not an HDF5 file

Error at Node 0: HDF Error occurred! at IO\Hdf\src\HdfFile_impl.hpp:157 during a call to HDF5 library function H5Fopen