Add pytest test suite (56 tests) for all spectrum components

tests/conftest.py

@@ -0,0 +1,35 @@
+# conftest.py — shared fixtures for pytest
+
+import numpy as np
+import pytest
+
+
+@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."""
+    # Endpoint at T = 2.5 MeV → W0 ≈ 5.9, so we go up to W=5.8
+    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)