Add test dependency

Author: wesselb

pyproject.toml

@@ -121,7 +121,7 @@ skip = [
 ]
 
 test-command = 'pytest {project}/tests -k "not incompatible_with_mypyc" --ignore={project}/tests/advanced'
-test-requires = ["pytest>=8.4.2"]
+test-requires = ["pytest>=8.4.2", "sybil[pytest]>=9.2.0"]
 # Skip testing arm64 builds on Intel Macs
 test-skip = ["*-macosx_arm64", "*-macosx_universal2:arm64"]
 
@@ -134,7 +134,6 @@ MYPYC_DEBUG_LEVEL = "0"
 manylinux-x86_64-image = "manylinux_2_28"
 manylinux-aarch64-image = "manylinux_2_28"
 
-
 # Development tools
 [tool.coverage]
 run.branch = true