Use subprocess to test module cleanup

Author: skirpichev

tests/test_functions.py

@@ -231,7 +231,6 @@ def test_interfaces():
         _mpmath_normalize(1, mpz(111), 1j, 12, 13, "c")
     with pytest.raises(ValueError, match="invalid rounding mode specified"):
         _mpmath_normalize(1, mpz(111), 11, 12, 13, 1j)
-    gmp._free_cache()  # just for coverage
 
 
 # See pypy/pypy#5368 and oracle/graalpython#593

tests/test_mpz.py

@@ -8,6 +8,7 @@
 import sys
 import warnings
 from concurrent.futures import ThreadPoolExecutor
+from subprocess import run
 
 import pytest
 from gmp import mpz
@@ -1092,3 +1093,10 @@ def test_int_api():
                 continue
         mz_sig = inspect.signature(mz)
         assert m_sig == mz_sig
+
+
+def test_mpz_clear():
+    # for coverage (test module cleanup)
+    res = run(["python", "-c",
+               "import gmp; a = gmp.mpz(1); del a; gmp._free_cache()"])
+    assert res.returncode == 0