feat: add notebook quality control pipeline with nbmake, auto-save hooks, and plot extraction

notebooks/conftest.py

@@ -0,0 +1,75 @@
+# conftest.py — shared fixtures for notebooks
+import matplotlib
+matplotlib.use("Agg")  # non-interactive backend for CI
+
+import matplotlib.pyplot as plt
+import numpy as np
+import os
+import pytest
+
+# Auto-save figures directory
+PLOTS_DIR = os.path.join(os.path.dirname(__file__), "_plots")
+os.makedirs(PLOTS_DIR, exist_ok=True)
+_plot_counter = 0
+
+
+def _save_figure_on_close(fig):
+    """Save figure to PNG before closing."""
+    global _plot_counter
+    plot_path = os.path.join(PLOTS_DIR, f"notebook_{_plot_counter:03d}.png")
+    try:
+        fig.savefig(plot_path, dpi=100, bbox_inches="tight")
+        _plot_counter += 1
+    except Exception:
+        pass
+
+
+# Patch plt.close to auto-save before closing
+_original_close = plt.close
+
+
+def _patched_close(fig=None):
+    if fig is not None:
+        _save_figure_on_close(fig)
+    return _original_close(fig)
+
+
+plt.close = _patched_close
+plt.rcParams.update({"figure.autolayout": True})
+
+
+@pytest.fixture(autouse=True)
+def close_figures():
+    """Close all matplotlib figures after each notebook cell execution."""
+    yield
+    plt.close("all")
+
+
+@pytest.fixture()
+def W_low():
+    """Low-energy total energy: T ≈ 10 keV → W = 1 + 0.01/0.511 ≈ 1.02."""
+    return np.array([1.02])
+
+
+@pytest.fixture()
+def W_mid():
+    """Mid-range energies (bulk of spectrum)."""
+    return np.linspace(1.1, 2.0, 5)
+
+
+@pytest.fixture()
+def W_high():
+    """High-energy total energy near endpoint: T ≈ 3 MeV → W ≈ 7."""
+    return np.array([6.8])
+
+
+@pytest.fixture()
+def W_full():
+    """Full spectrum grid from ~1 keV to just below endpoint."""
+    return np.linspace(1.003, 5.8, 100)
+
+
+@pytest.fixture()
+def large_W():
+    """Large array for performance/shape checks."""
+    return np.linspace(1.002, 4.9, 1000)