Add reproducer for issue #14.

3 files changed, 25 insertions, 5 deletions

diff --git a/pyecsca/ec/formula.py b/pyecsca/ec/formula.py
index ef206ab..0188271 100644
--- a/pyecsca/ec/formula.py
+++ b/pyecsca/ec/formula.py
@@ -200,7 +200,8 @@ class Formula(ABC):
                     break
                 else:
                     raise UnsatisfiedAssumptionError(
-                        f"Unsatisfied assumption in the formula ({assumption_string})."
+                        f"Unsatisfied assumption in the formula ({assumption_string}).\n"
+                        f"'{expr}' has no roots in the base field {k}."
                     )
 
     def __call__(self, field: int, *points: Any, **params: Mod) -> Tuple[Any, ...]:
diff --git a/test/ec/test_regress.py b/test/ec/test_regress.py
index 9304c9e..4cb5f3c 100644
--- a/test/ec/test_regress.py
+++ b/test/ec/test_regress.py
@@ -1,15 +1,16 @@
 from typing import cast
-from unittest import TestCase
+from unittest import TestCase, skip
 from sympy import symbols
 
 from pyecsca.ec.coordinates import AffineCoordinateModel
 from pyecsca.ec.curve import EllipticCurve
+from pyecsca.ec.error import UnsatisfiedAssumptionError
 from pyecsca.ec.formula import AdditionFormula, DoublingFormula, ScalingFormula
 from pyecsca.ec.mod import Mod, SymbolicMod
 from pyecsca.ec.model import MontgomeryModel, EdwardsModel
 from pyecsca.ec.params import get_params
 from pyecsca.ec.mult import LTRMultiplier
-from pyecsca.ec.point import Point
+from pyecsca.ec.point import Point, InfinityPoint
 
 
 class RegressionTests(TestCase):
@@ -91,3 +92,22 @@ class RegressionTests(TestCase):
         Q = Point(coords, Y=SymbolicMod(yq, p), Z=SymbolicMod(zq, p))
         formula = coords.formulas["dadd-2006-g-2"]
         formula(p, PmQ, P, Q, c=c, r=r, d=d)
+
+    @skip("Unresolved issue currently.")
+    def test_issue_14(self):
+        model = EdwardsModel()
+        coords = model.coordinates["projective"]
+        affine = AffineCoordinateModel(model)
+        formula = coords.formulas["add-2007-bl-4"]
+        p = 19
+        c = Mod(2, p)
+        d = Mod(10, p)
+        curve = EllipticCurve(model, coords, p, InfinityPoint(coords), {"c": c, "d": d})
+        Paff = Point(affine, x=Mod(0xd, p), y=Mod(0x9, p))
+        P = Paff.to_model(coords, curve)
+        Qaff = Point(affine, x=Mod(0x4, p), y=Mod(0x12, p))
+        Q = Qaff.to_model(coords, curve)
+        PQaff = curve.affine_add(Paff, Qaff)
+        R = formula(p, P, Q, **curve.parameters)[0]
+        Raff = R.to_affine()
+        self.assertEqual(PQaff, Raff)
diff --git a/test/sca/test_rpa.py b/test/sca/test_rpa.py
index b33915e..1f06e92 100644
--- a/test/sca/test_rpa.py
+++ b/test/sca/test_rpa.py
@@ -66,10 +66,9 @@ class MultipleContextTests(TestCase):
 
     def test_window(self):
         mult = WindowNAFMultiplier(self.add, self.dbl, self.neg, 3, precompute_negation=True)
-        with local(MultipleContext()) as ctx:
+        with local(MultipleContext()):
             mult.init(self.secp128r1, self.base)
             mult.multiply(5)
-        print(ctx.points.values())
 
     def test_ladder(self):
         curve25519 = get_params("other", "Curve25519", "xz")