t/op/numify.t: More tests to check if invalid Inf/NaNs are not numified

t/op/numify.t

@@ -11,6 +11,11 @@ BEGIN {
 use strict;
 use warnings;
 
+# Quick test if NV supports infinities.
+# Note that this would be $Config{d_double_has_inf}, but this is only valid
+# if NV is configured as double.
+my $nv_has_inf = do { no warnings; 'inf' > 0 };
+
 foreach ([' +3', 3, 0],
          ["10.\t", 10, 0],
          ['abc', 0, 1],
@@ -22,7 +27,14 @@ foreach ([' +3', 3, 0],
          ['- 0x789', 0, 1],
          ['0b101', 0, 1],
          ['-3.14', -3.14, 0],
-         ['- 3.14', 0, 1]) {
+         ['- 3.14', 0, 1],
+         ($nv_has_inf ?
+          (['+infinity ', '+Inf', 0],
+           ['  -infin', '-Inf', 1],
+           ['+ inf', 0, 1],
+           ['+-inf', 0, 1]) :
+          ())
+    ) {
     my ($str, $num, $warn) = @$_;
 
     my $code = sub {