t_nextafter: Test corner case, x == y

Thanks to asau@ for bringing this into my attention.

diff --git a/math/t_nextafter.c b/math/t_nextafter.c
index e26bf60..cf6ee0e 100644 (file)
--- a/math/t_nextafter.c
+++ b/math/t_nextafter.c
@@ -231,6 +231,44 @@ ATF_TC_BODY(test_nextafter4, tc)
 #endif /* INFINITY */
 }
 
+/*
+ * Test case 5
+ * http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44875
+ */
+ATF_TC(test_nextafter5);
+ATF_TC_HEAD(test_nextafter5, tc)
+{
+       atf_tc_set_md_var(tc,
+           "descr",
+           "If x == y, y (of the type x) shall be returned");
+}
+ATF_TC_BODY(test_nextafter5, tc)
+{
+       float fx, fy;
+       double dx, dy;
+       long double ldx, ldy;
+
+       /* float */
+       fy = nextafterf(-0.0, +0.0);
+       ATF_CHECK(iszero(fy) && signbit(fy) == 0);
+       fy = nextafterf(+0.0, -0.0);
+       ATF_CHECK(iszero(fy) && signbit(fy) == 1);
+
+       /* double */
+       dy = nextafter(-0.0, +0.0);
+       ATF_CHECK(iszero(dy) && signbit(dy) == 0);
+       dy = nextafterf(+0.0, -0.0);
+       ATF_CHECK(iszero(dy) && signbit(dy) == 1);
+
+       /* long double */
+#ifdef HAVE_NEXTAFTERL
+       ldy = nextafterfl(-0.0, +0.0);
+       ATF_CHECK(iszero(ldy) && signbit(ldy) == 0);
+       ldy = nextafterfl(+0.0, -0.0);
+       ATF_CHECK(iszero(ldy) && signbit(ldy) == 1);
+#endif
+}
+
 /* Add test cases to test program */
 ATF_TP_ADD_TCS(tp)
 {
@@ -238,6 +276,7 @@ ATF_TP_ADD_TCS(tp)
        ATF_TP_ADD_TC(tp, test_nextafter2);
        ATF_TP_ADD_TC(tp, test_nextafter3);
        ATF_TP_ADD_TC(tp, test_nextafter4);
+       ATF_TP_ADD_TC(tp, test_nextafter5);
 
        return atf_no_error();
 }