Move OSS-Fuzz target file under tests

pyproject.toml

@@ -51,6 +51,9 @@ doc = [
 benchmarks = [
     "pytest-benchmark==4.0.0",
 ]
+fuzz = [
+    "atheris",
+]
 
 [project.scripts]
 cbor2 = "cbor2.tool:main"

tests/fuzzers/loads_fuzzer.py

@@ -0,0 +1,22 @@
+import sys
+import atheris
+
+# _cbor2 ensures the C library is imported
+from _cbor2 import loads
+
+
+def test_one_input(data: bytes):
+    try:
+        loads(data)
+    except Exception:
+        # We're searching for memory corruption, not Python exceptions
+        pass
+
+
+def main():
+    atheris.Setup(sys.argv, test_one_input)
+    atheris.Fuzz()
+
+
+if __name__ == "__main__":
+    main()