FLASH PR Refactor How Fits Files are Loaded to Remove String Formatting

[JackEAllen]

Issue

FLASH PR

Description

Change implementation of how .fits files are read into the live viewer (mantidimaging/gui/windows/live_viewer/presenter.py:112).

Using __str__(), which is a special method directly which is normally used by str() does not respect the encapsulation of the object's implementation and can be less explicit. This in turn means using __str__() could be considered less Pythonic. This PR removes the use of __str__() as string formatting is not necessary.

As load_image() states that an np.ndarray should be returned, I have also assigned image_data to an empty array (np.array([])) to cover the case where neither a .tif, .tiff or .fits file is in the suffix of the path used as an argument to load_image() to resolve 'image_data' before assignment - Pylint where image_data was not previously assigned if neither case was met.

Testing

Describe the tests that you were used to verify your changes.

• Checked that unit tests pass
• Tested live viewer with simulate live viewer utility script (scripts/simulate_live_data.py) with .fits files.

Acceptance Criteria

Acceptance criteria for reviewer to tick off in order to verify your changes.

• .fits files can correctly be loaded and read by live viewer
  • Verify that opening a pre-existing dataset in the live viewer that uses .fits still works as it did on main
  • Verify using the scripts/simulate_live_data.py script that the live viewer loads in .fits files as they arrive in a selected folder

Documentation

How have you changed the documentation to reflect your changes? All changes should be noted in the appropriate file in docs/release_notes

N/A not needed.

[coveralls]

coverage: 73.6% (-0.009%) from 73.609%
when pulling c2f20e5 on live_view_read_fits
into a2e5302 on main.

[samtygier-stfc]

Looks good, and works locally.