add tests for fluence rate and attenuation interpolation

tests/test_attenuation_functions.py

@@ -0,0 +1,30 @@
+import pytest
+
+from pg_rad.physics import get_mass_attenuation_coeff
+
+
+@pytest.mark.parametrize("energy,mu", [
+    (1.00000E-03, 3.606E+03),
+    (1.00000E-02, 5.120E+00),
+    (1.00000E-01, 1.541E-01),
+    (1.00000E+00, 6.358E-02),
+    (1.00000E+01, 2.045E-02) 
+])
+def test_exact_attenuation_retrieval(energy, mu):
+    """
+    Test if retrieval of values that are exactly in the table is correct.
+    """
+    func_mu = get_mass_attenuation_coeff(energy)
+    assert pytest.approx(func_mu, rel=1E-6) == mu
+
+
+@pytest.mark.parametrize("energy,mu", [
+    (0.662, 0.0778),
+    (1.25, 0.06)
+])
+def test_attenuation_interpolation(energy, mu):
+    """
+    Test Cs-137 and Co-60 mass attenuation coefficients.
+    """
+    interp_mu = get_mass_attenuation_coeff(energy)
+    assert pytest.approx(interp_mu, rel=1E-2) == mu

tests/test_fluence_rate.py

@@ -0,0 +1,41 @@
+from math import dist, exp, pi
+
+import pytest
+
+from pg_rad.isotopes import CS137
+from pg_rad.landscape import Landscape
+from pg_rad.objects import PointSource
+
+
+@pytest.fixture
+def phi_ref():
+    A = 100                             # MBq
+    b = 0.851
+    mu_mass_air = 0.0778                # cm^2/g
+    air_density = 1.243                 # kg/m^3
+    r = dist((0, 0, 0), (10, 10, 0))    # m
+
+    A *= 1E9                            # Convert to Bq
+    mu_mass_air *= 0.1                  # Convert to m^2/kg
+
+    mu_air = mu_mass_air * air_density  # [m^2/kg] x [kg/m^3] = [m^-1]
+
+    # [s^-1] x exp([m^-1] x [m]) / [m^-2] = [s^-1 m^-2]
+    phi = A * b * exp(-mu_air * r) / (4 * pi * r**2)
+    return phi
+
+
+@pytest.fixture
+def test_landscape():
+    landscape = Landscape()
+    source = PointSource(
+        pos=(0, 0, 0),
+        activity=100E9,
+        isotope=CS137)
+    landscape.add_sources(source)
+    return landscape
+
+
+def test_single_source_fluence(phi_ref, test_landscape):
+    phi = test_landscape.calculate_fluence_at((10, 10, 0))
+    assert pytest.approx(phi, rel=1E-3) == phi_ref