diff -dupr a/test2/gmpy_test.py b/test2/gmpy_test.py
--- a/test2/gmpy_test.py	2019-11-22 09:21:42.313037873 +0100
+++ b/test2/gmpy_test.py	2013-08-20 22:17:52.000000000 +0200
@@ -34,11 +34,15 @@ writeln("  Caching Values: (Number)
 writeln("  Caching Values: (Size, limbs) {0}".format(_g.get_cache()[1]))
 
 pf, pt = 0, 0
+ret = 0
 for x in test_modules:
     testit = x._test()
     failures, tests = testit
     if tests == 0: continue
+    if failures > 0: ret = 1
     writeln("%s %3d tests, %d failures" % (x.__name__, tests-pt, failures-pf))
     pf, pt = failures, tests
 
 doctest.master.summarize(1)
+
+sys.exit(ret)
diff -dupr a/test3/gmpy_test.py b/test3/gmpy_test.py
--- a/test3/gmpy_test.py	2019-11-22 09:21:30.421908749 +0100
+++ b/test3/gmpy_test.py	2013-08-20 22:17:52.000000000 +0200
@@ -28,10 +28,12 @@ print("  Caching Values: (Number)      {
 print("  Caching Values: (Size, limbs) {0}".format(_g.get_cache()[1]))
 
 pf, pt = 0, 0
+ret = 0
 for x in test_modules:
     testit = x._test()
     failures, tests = testit
     if tests == 0: continue
+    if failures > 0: ret = 1
     print("%s %3d tests, %d failures" % (x.__name__, tests-pt, failures-pf))
     pf, pt = failures, tests
 
@@ -41,3 +43,5 @@ if sys.version_info < (3,1,1):
     print("There is a known bug with Fraction == mpq for versions of Python")
     print("less than 3.1.1. Please upgrade if you rely on comparisons between")
     print("Python's Fraction and gmpy2's mpq.")
+
+sys.exit(ret)