diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 368676a3..d105cd48 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -32,26 +32,19 @@ jobs:
 
       - name: Install test dependencies
         run: |
-          sudo add-apt-repository -y ppa:deadsnakes/ppa
           sudo apt-get -y install \
             valgrind \
-            gdb \
-            python${{ matrix.python-version }} \
-            python3.10{,-full}
-
-      # Using these actions lead to Python binaries that cause SIGSEGV during
-      # C unit tests. See
-      # https://github.com/actions/setup-python/issues/442.
-
-      # - name: Install Python
-      #   uses: actions/setup-python@v4
-      #   with:
-      #     python-version: ${{ matrix.python-version }}
-
-      # - name: Install Python 3.10
-      #   uses: actions/setup-python@v4
-      #   with:
-      #     python-version: "3.10"
+            gdb
+
+      - name: Install Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}-dev
+
+      - name: Install Python 3.10
+        uses: actions/setup-python@v4
+        with:
+          python-version: "3.10"
 
       - name: Compile Austin
         run: |
diff --git a/test/cunit/__init__.py b/test/cunit/__init__.py
index 5ebe70a3..9458b48f 100644
--- a/test/cunit/__init__.py
+++ b/test/cunit/__init__.py
@@ -1,10 +1,10 @@
 import ctypes
 import re
-from ctypes import CDLL, POINTER, Structure, c_char_p, cast
+from ctypes import CDLL, POINTER, Structure, c_char_p, c_long, c_void_p, cast
 from pathlib import Path
 from subprocess import PIPE, STDOUT, run
 from types import ModuleType
-from typing import Any, Callable, Optional, Type
+from typing import Any, Callable, Optional, Type, Union
 
 from pycparser import c_ast, c_parser
 from pycparser.plyparser import ParseError
@@ -90,7 +90,9 @@ def compile(
 
 
 class CFunctionDef:
-    def __init__(self, name: str, args: list[str], rtype: Any) -> None:
+    def __init__(
+        self, name: str, args: list[tuple[str, Type[ctypes._SimpleCData]]], rtype: Any
+    ) -> None:
         self.name = name
         self.args = args
         self.rtype = rtype
@@ -101,7 +103,7 @@ def __init__(self, name: str, fields: list[str]) -> None:
         self.name = name
         self.fields = fields
         self.methods = []
-        self.constructor = False
+        self.constructor = None
 
 
 class CType(Structure):
@@ -113,16 +115,20 @@ def __del__(self) -> None:
             self.destroy()
 
     def __repr__(self) -> str:
-        return f"<{self.name} CObject at {self.__cself__}>"
+        return f"<{self.__class__.__name__} CObject at {self.__cself__}>"
 
 
 class CFunction:
     def __init__(self, cfuncdef: CFunctionDef, cfunc: Callable[..., Any]) -> None:
         self.__name__ = cfuncdef.name
-        self.__args__ = cfuncdef.args
+        self.__args__ = [_[0] for _ in cfuncdef.args]
         self.__cfunc__ = cfunc
-        if cfuncdef.rtype is not None:
-            self.__cfunc__.restype = cfuncdef.rtype
+
+        # Prevent argument values from being truncated/mangled
+        self.__cfunc__.argtypes = [_[1] for _ in cfuncdef.args]
+        self.__cfunc__.restype = (
+            cfuncdef.rtype if cfuncdef.rtype is not None else c_long
+        )
 
         self._posonly = all(_ is None for _ in self.__args__)
 
@@ -207,7 +213,6 @@ def __init__(self) -> None:
         self.functions = []
 
     def _get_type(self, node: c_ast.Node) -> None:
-        print(node)
         return self.types[" ".join(node.type.type.names)]
 
     def visit_Typedef(self, node: c_ast.Node) -> None:
@@ -231,8 +236,16 @@ def visit_Decl(self, node: c_ast.Node) -> None:
             if isinstance(ret_type, c_ast.PtrDecl):
                 if "".join(ret_type.type.type.names) == "char":
                     rtype = c_char_p
+                else:
+                    rtype = c_void_p
+
             args = (
-                [_.name if hasattr(_, "name") else None for _ in node.type.args.params]
+                [
+                    (_.name, c_void_p if isinstance(_.type, c_ast.PtrDecl) else c_long)
+                    if hasattr(_, "name")
+                    else None
+                    for _ in node.type.args.params
+                ]
                 if node.type.args is not None
                 else []
             )
@@ -271,7 +284,7 @@ def collect(self, decl: str) -> dict[str, CTypeDef]:
         return {
             k: v
             for k, v in self.types.items()
-            if isinstance(v, CTypeDef) and v.constructor
+            if isinstance(v, CTypeDef) and v.constructor is not None
         }
 
 
diff --git a/test/cunit/test_cache.py b/test/cunit/test_cache.py
index ec809bd1..84a41844 100644
--- a/test/cunit/test_cache.py
+++ b/test/cunit/test_cache.py
@@ -1,9 +1,12 @@
+from ctypes import c_void_p
 from test.cunit import C
 from test.cunit.cache import Chain, HashTable, LruCache, Queue, QueueItem
 
 import pytest
 
 NULL = 0
+C.free.argtypes = [c_void_p]
+C.malloc.restype = c_void_p
 
 
 def test_queue_item():
@@ -31,7 +34,7 @@ def test_queue(qsize):
 
     assert qsize == 0 or not q.is_empty()
     assert q.is_full()
-    assert q.enqueue(42, 42) is NULL
+    assert q.enqueue(42, 42) is None
 
     assert values == [q.dequeue() for _ in range(qsize)]
 
diff --git a/test/utils.py b/test/utils.py
index f659ff28..2b89f035 100644
--- a/test/utils.py
+++ b/test/utils.py
@@ -27,6 +27,7 @@
 from collections import Counter, defaultdict
 from io import BytesIO, StringIO
 from pathlib import Path
+from shutil import rmtree
 from subprocess import PIPE, CompletedProcess, Popen, check_output, run
 from test import PYTHON_VERSIONS
 from time import sleep
@@ -109,7 +110,7 @@ def bt(binary: Path) -> str:
             result = gdb(["bt full", "q"], str(binary), target_dir / "CoreDump")
 
             crash.unlink()
-            target_dir.rmdir()
+            rmtree(str(target_dir))
 
             return result