Try abspath

Author: stefanv

spin/tests/test_build_cmds.py

@@ -43,7 +43,7 @@ def test_debug_builds(example_pkg):
 
 def test_prefix_builds(example_pkg):
     """does spin build --prefix create a build-install directory with the correct structure?"""
-    spin("build", f"--prefix={os.path.normpath('/foobar/')}")
+    spin("build", f"--prefix={os.path.abspath('/foobar')}")
     assert (Path("build-install") / Path("foobar")).exists()