[QDP] [Test] Add and refactor NumPy encoding tests

[viiccwen]

Summary

Add and refactor NumPy encoding tests in test_numpy.py to improve maintainability and add 2D array batch encoding test coverage.

Use Case

The NumPy encoding tests were lacked coverage for 2D array batch encoding scenarios. This refactoring:

1. Adds 2D array testing - Ensures batch encoding works correctly for 2D NumPy arrays
2. Follows pytest best practices - Removes unnecessary if __name__ == "__main__": blocks
3. Improves maintainability - Uses helper functions and parameterized tests for cleaner code

Proposed Implementation

1. Added 2D array batch encoding tests

   • Extended test_encode_numpy_array() to test both 1D (single sample) and 2D (batch) arrays
   • Tests various batch sizes and qubit configurations

2. Code cleanup

   • Removed redundant if __name__ == "__main__": block (pytest handles test discovery automatically)
   • Removed unnecessary print statements
   • Fixed tests to only test implemented encoding methods (amplitude, not angle/basis)

3. Test coverage

   • NumPy file format encoding (.npy files)
   • 1D NumPy array encoding (single sample)
   • 2D NumPy array encoding (batch)
   • Different precision settings (float32, float64)
   • Error handling (wrong dtype, unsupported dimensions)

[viiccwen]

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