add pytest to cover pcacs

tests/test_efaar.py

@@ -1,3 +1,4 @@
+import pytest
 import numpy as np
 import pandas as pd
 from anndata import AnnData
@@ -63,3 +64,30 @@ def test_filter_cell_profiler_features():
     filtered_features, _ = efaar.filter_cell_profiler_features(features, metadata)
     assert not filtered_features.empty
     assert "Image_Granularity_12_ER" not in filtered_features.columns
+
+
+@pytest.mark.parametrize(
+    "metadata, expected_shape, expect_error",
+    [
+        (
+            pd.DataFrame({"perturbation": ["control", "control", "treatment", "treatment"], "batch": [1, 1, 1, 1]}),
+            (4, 2),
+            False,
+        ),
+        (
+            pd.DataFrame({"perturbation": ["treatment", "treatment", "treatment", "treatment"], "batch": [1, 1, 1, 1]}),
+            None,
+            True,
+        ),
+    ],
+)
+def test_pca_centerscale_on_controls(metadata, expected_shape, expect_error):
+    embeddings = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]])
+    pert_col = "perturbation"
+    control_key = "control"
+    if expect_error:
+        with pytest.raises(ValueError, match=f"No control samples found for {control_key}"):
+            efaar.pca_centerscale_on_controls(embeddings, metadata, pert_col, control_key, None)
+    else:
+        result = efaar.pca_centerscale_on_controls(embeddings, metadata, pert_col, control_key, None)
+        assert result.shape == expected_shape