Fix pixi run test: CUDA 13.3 pin lag + cython-test .so placement

cuda_bindings/pixi.toml

@@ -10,7 +10,7 @@ preview = ["pixi-build"]
 [workspace.build-variants]
 python = ["3.10.*", "3.11.*", "3.12.*", "3.13.*", "3.14.*"]
 # Keep source-package metadata aligned with the consuming environment's CUDA major.
-cuda-version = ["12.*", "13.2.*"]
+cuda-version = ["12.*", "13.3.*"]
 
 [feature.test.dependencies]
 cuda-bindings = { path = "." }
@@ -74,7 +74,7 @@ CUDA_HOME = "$CONDA_PREFIX/Library"
 cuda-version = "12.*"
 
 [feature.cu13.dependencies]
-cuda-version = "13.2.*"
+cuda-version = "13.3.*"
 
 [environments]
 default = { features = ["test", "cython-tests"], solve-group = "default" }

cuda_bindings/tests/cython/build_tests.py

@@ -12,6 +12,7 @@
 
 from __future__ import annotations
 
+import os
 import sys
 from pathlib import Path
 
@@ -45,6 +46,13 @@ def main() -> None:
         compiler_directives={"freethreading_compatible": True},
     )
 
+    # `build_ext --inplace` places the compiled .so relative to the current
+    # working directory, but pixi runs this task from the project root. pytest
+    # imports each extension by bare module name (see test_cython.py), which
+    # only resolves when the .so sits in tests/cython (the dir pytest puts on
+    # sys.path). chdir here so the .so lands next to its .pyx regardless of the
+    # invoking cwd.
+    os.chdir(script_dir)
     sys.argv = [sys.argv[0], "build_ext", "--inplace"]
     setup(name="cuda_bindings_cython_tests", ext_modules=ext_modules)