added nifti unit tests

tests/eva/vision/utils/io/test_nifti.py

@@ -0,0 +1,53 @@
+"""Tests for the nifti IO functions."""
+
+import os
+
+import nibabel as nib
+import numpy as np
+import pytest
+from nibabel import orientations
+
+from eva.vision.utils.io import nifti
+
+
+@pytest.mark.parametrize(
+    "use_storage_dtype, target_orientation",
+    [
+        [False, None],
+        [False, "LPS"],
+        [True, "RAS"],
+    ],
+)
+def test_read_nifti(nifti_path: str, use_storage_dtype: bool, target_orientation: str):
+    """Tests the function to read a nifti file as array (full & slice)."""
+    image = nifti.read_nifti(
+        nifti_path, use_storage_dtype=use_storage_dtype, target_orientation=target_orientation
+    )
+    assert image.shape == (512, 512, 4)
+
+    slice_image = nifti.read_nifti(
+        nifti_path,
+        slice_index=0,
+        use_storage_dtype=use_storage_dtype,
+        target_orientation=target_orientation,
+    )
+    assert slice_image.shape == (512, 512, 1)
+
+    expected_dtype = np.dtype("<i2") if use_storage_dtype else np.float_
+    assert image.dtype == expected_dtype
+
+
+@pytest.mark.parametrize("orientation", ["LPS", "LAS", "LAI", "RAS", "RPS"])
+def test_reorient(nifti_path: str, orientation: str):
+    """Tests the reorientation of a nifti image."""
+    original_image = nib.load(nifti_path)
+    reoriented_image = nifti.reorient(original_image, orientation)
+
+    assert "RAS" == "".join(orientations.aff2axcodes(original_image.affine))
+    assert orientation == "".join(orientations.aff2axcodes(reoriented_image.affine))
+
+
+@pytest.fixture()
+def nifti_path(assets_path: str):
+    """Path to a nifti test asset file."""
+    return os.path.join(assets_path, "vision/datasets/kits23/case_00036/master_00036.nii.gz")