diff --git a/tests/float/math_domain_special.py b/tests/float/math_domain_special.py
index 388920350e..5650c35fec 100644
--- a/tests/float/math_domain_special.py
+++ b/tests/float/math_domain_special.py
@@ -26,7 +26,7 @@ for name, f, args in (
     ('gamma', math.gamma, (-2, -1, 0, 1)),
     ('lgamma', math.lgamma, (-2, -1, 0, 1)),
     ):
-    for x in args + (inf, nan):
+    for x in args + (inf, -inf, nan):
         try:
             ans = f(x)
             print('%.4f' % ans)
diff --git a/tests/float/math_fun_special.py b/tests/float/math_fun_special.py
index c3665a7cd9..e676a6fc97 100644
--- a/tests/float/math_fun_special.py
+++ b/tests/float/math_fun_special.py
@@ -16,7 +16,7 @@ functions = [
     ('log10', log10, test_values),
     ('cosh', cosh, test_values),
     ('sinh', sinh, test_values),
-    ('tanh', tanh, test_values),
+    ('tanh', tanh, [-1e6, -100] + test_values + [100, 1e6]),
     ('acosh', acosh, [1.0, 5.0, 1.0]),
     ('asinh', asinh, test_values),
     ('atanh', atanh, [-0.99, -0.5, 0.0, 0.5, 0.99]),