[SYSTEMDS-3971] Refactor redundant Scuro tests

[shieru1214]

1. Purpose

This PR only changes test files and does not change the Scuro source code. The main purpose is to identify redundant or overly large component tests and refactor them into smaller tests, while also reducing the runtime if possible.

2. Overview

This PR focuses on the representation operator, window operation, and fusion parts.

Stage	File	Main change
Representation Operator	test_unimodal_optimizer.py	Combines five modality optimizer tests into one test
Representation Operator	test_unimodal_representations.py	Reuses the existing audio modality helper
Window Operation	test_window_operations.py	Combines repeated 1D modality tests and the separate 2D and 3D shape tests
Fusion	test_fusion_orders.py	Combines four fusion tests

3. Changes

3.1 Representation Operator

In test_unimodal_optimizer.py, the text, image, audio, video, and text-image tests previously created their modalities separately before calling the same optimizer helper. I moved the shared codes and loader setup into create_modality, while the input modalities are stored in MODALITY_SETS.

This keeps the differences between the five cases visible in one place. Each case is executed as a subtest, so a failure directly shows which modality combination caused it.

In test_unimodal_representations.py, I reused the existing create_audio_modality helper in test_audio_representations. This removes a repeated block that created the audio data, loader, and modality. The audio setup can be maintained in one place.

3.2 Window Operation

In test_window_operations.py, the audio, video, and text cases all applied the same four window aggregations to 1D data. These inputs have the same data layout (single level), and the aggregation path is selected by DataLayout rather than ModalityType.

I combined the three methods into one test that runs three modalities and four aggregation methods, keeping all 12 combinations. A failure now reports both the modality and aggregation method, instead of only the name of the original test method.

I also combined the separate 2D and 3D shape tests. Both tests used the same three window operators, and their expected output shapes follow the same rule. The new test keeps all six combinations of two dimensions and three operators. Each case includes dims and operator labels, which makes it easier to find the failing combination.

3.3 Fusion

In test_fusion_orders.py, the separate tests for Average, Concatenation, RowMax, and Hadamard followed the same fusion steps. I combined them into FUSION_PROPERTIES and one shared test method with four subtests.

FUSION_PROPERTIES stores whether switching the first two inputs changes the chained result, and whether chained fusion gives the same result as combining all three inputs in one call. And commutativity is checked by comparing the actual result with the operator's commutative attribute. This checks whether the declared property agrees with the implementation. Another compatible fusion operator can be covered by adding one entry to the table.

This PR also changes the previous Concatenation comparison. The old test compared a two-input result with a three-input result, which were already different in shape. The new test compares chained three-input fusion with direct three-input fusion, so all four operators now use the same comparison.

Finally, the fusion input size was reduced. The test checks input order and fusion calling style rather than data size, so the smaller input follows the same test path while processing less data.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.90%. Comparing base (0a245ab) to head (929d9ff).
⚠️ Report is 19 commits behind head on main.

Additional details and impacted files

@@              Coverage Diff              @@
##               main    #2614       +/-   ##
=============================================
+ Coverage     71.39%   74.90%    +3.50%     
=============================================
  Files          1632      436     -1196     
  Lines        196237    25189   -171048     
  Branches      38201        0    -38201     
=============================================
- Hits         140113    18869   -121244     
+ Misses        45099     6320    -38779     
+ Partials      11025        0    -11025     

Flag	Coverage Δ
python	74.90% <100.00%> (?)

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