chore: checkpoint before Python removal

vendor/p521/tests/projective.rs

@@ -0,0 +1,21 @@
+//! Projective arithmetic tests.
+
+#![cfg(all(feature = "arithmetic", feature = "test-vectors"))]
+
+use elliptic_curve::{
+    group::ff::PrimeField,
+    sec1::{self, ToEncodedPoint},
+};
+use p521::{
+    test_vectors::group::{ADD_TEST_VECTORS, MUL_TEST_VECTORS},
+    AffinePoint, ProjectivePoint, Scalar,
+};
+use primeorder::{impl_projective_arithmetic_tests, Double};
+
+impl_projective_arithmetic_tests!(
+    AffinePoint,
+    ProjectivePoint,
+    Scalar,
+    ADD_TEST_VECTORS,
+    MUL_TEST_VECTORS
+);