test: solve recovers expected parameters

Author: jokasimr

tests/estia/calibration_test.py

@@ -1,5 +1,9 @@
 import numpy as np
+import pytest
 import scipp as sc
+from scipp.testing import assert_allclose
+
+from ess.estia.calibration import solve_for_calibration_parameters
 
 
 def generate_valid_calibration_parameters():
@@ -44,3 +48,22 @@ def intensity_from_parameters(I0, Pp, Pa, Ap, Aa, Rpp, Rpa, Rap, Raa):
             + Raa * (1 - Aa) * (1 - Pa)
         ),
     )
+
+
+@pytest.mark.parametrize("seed", range(10))
+def test_calibration_solve_recovers_input(seed):
+    np.random.seed(seed)
+    I0, Pp, Pa, Ap, Aa, Rspp, Rsaa = generate_valid_calibration_parameters()
+    Io = intensity_from_parameters(
+        I0, Pp, Pa, Ap, Aa, sc.scalar(1), sc.scalar(0), sc.scalar(0), sc.scalar(1)
+    )
+    Is = intensity_from_parameters(
+        I0, Pp, Pa, Ap, Aa, Rspp, sc.scalar(0), sc.scalar(0), Rsaa
+    )
+    tuple(
+        map(
+            assert_allclose,
+            solve_for_calibration_parameters(Io, Is),
+            (I0, Pp, Pa, Ap, Aa, Rspp, Rsaa),
+        )
+    )