feat(eeg): add is_valid_epoch guard for NaN/inf/shape/dtype

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pipelines/eeg_pipeline.py

@@ -0,0 +1,37 @@
+"""EEG (electroencephalography) pipeline.
+
+Loads raw recordings (FIF/EDF), bandpass-filters, removes EOG artifacts via
+ICA, slices into fixed-duration epochs, computes per-band PSD + statistical
+features, flattens to a 2D table, and writes a model-ready Parquet at
+`data/processed/eeg_features.parquet`.
+
+Follows the Data Readiness contract in AGENTS.md §4 and the Parquet storage
+convention in §6: schema validity, domain validity (drop NaN/inf epochs with
+a logged WARNING), determinism (seeded ICA + sklearn RNG), traceability
+(in/out/dropped counts at INFO), and idempotent overwrite output.
+"""
+from __future__ import annotations
+
+import numpy as np
+
+from src.core.logger import get_logger
+
+logger = get_logger(__name__)
+
+
+def is_valid_epoch(epoch: object) -> bool:
+    """Return True iff `epoch` is a non-empty 2-D float array with no NaN/inf.
+
+    Used to drop corrupted segments before feature extraction. Defensive
+    against the full set of garbage we expect from real recordings: lists,
+    None, NaN/inf samples, zero-sized arrays.
+    """
+    if not isinstance(epoch, np.ndarray):
+        return False
+    if epoch.ndim != 2:
+        return False
+    if epoch.size == 0:
+        return False
+    if not np.all(np.isfinite(epoch)):
+        return False
+    return True

tests/pipelines/test_eeg_pipeline.py

@@ -0,0 +1,40 @@
+"""Unit + integration tests for the EEG pipeline."""
+from __future__ import annotations
+
+from pathlib import Path
+
+import numpy as np
+import pytest
+
+from src.pipelines.eeg_pipeline import is_valid_epoch
+
+
+FIXTURE = Path(__file__).parent.parent / "fixtures" / "eeg_sample.fif"
+
+
+class TestIsValidEpoch:
+    def test_accepts_2d_finite_array(self) -> None:
+        epoch = np.zeros((4, 256), dtype=np.float64)
+        assert is_valid_epoch(epoch) is True
+
+    def test_rejects_wrong_dimension(self) -> None:
+        assert is_valid_epoch(np.zeros((4,))) is False
+        assert is_valid_epoch(np.zeros((4, 256, 2))) is False
+
+    def test_rejects_nan(self) -> None:
+        epoch = np.zeros((4, 256))
+        epoch[0, 10] = np.nan
+        assert is_valid_epoch(epoch) is False
+
+    def test_rejects_inf(self) -> None:
+        epoch = np.zeros((4, 256))
+        epoch[1, 5] = np.inf
+        assert is_valid_epoch(epoch) is False
+
+    def test_rejects_empty(self) -> None:
+        assert is_valid_epoch(np.zeros((0, 256))) is False
+        assert is_valid_epoch(np.zeros((4, 0))) is False
+
+    def test_rejects_non_array(self) -> None:
+        assert is_valid_epoch([[1, 2, 3]]) is False
+        assert is_valid_epoch(None) is False