[io grant] Test IO::Path.child-secure

Also add a nul byte test to IO::Path.child.

S32-io/io-path.t

@@ -3,7 +3,7 @@ use lib <t/spec/packages/>;
 use Test;
 use Test::Util;
 
-plan 29;
+plan 30;
 
 # L<S32::IO/IO::Path>
 
@@ -179,3 +179,36 @@ subtest '.link' => {
             'fail when link already exists';
     }
 }
+
+subtest '.child-secure' => {
+    my $parent = make-temp-dir;
+    my $non-resolving-parent = make-temp-file.child('bar');
+
+    fails-like { $non-resolving-parent.child-secure('../foo') }, X::IO::Resolve,
+        'non-resolving parent fails (given path is non-child)';
+
+    fails-like { $non-resolving-parent.child-secure('foo') }, X::IO::Resolve,
+        'non-resolving parent fails (given path is child)';
+
+    fails-like { $parent.child-secure('foo/bar') }, X::IO::Resolve,
+        'resolving parent fails (given path is a child, but not resolving)';
+
+    fails-like { $parent.child-secure('../foo') }, X::IO::NotAChild,
+        'resolved parent fails (given path is not a child)';
+
+    is-path $parent.child-secure('foo'), $parent.child('foo'),
+        'resolved parent with resolving, non-existent child';
+
+    $parent.child-secure('foo').mkdir;
+    is-path $parent.child-secure('foo'), $parent.child('foo'),
+        'resolved parent with resolving, existent child';
+
+    is-path $parent.child-secure('foo/bar'), $parent.child('foo/bar'),
+        'resolved parent with resolving, existent child in a subdir';
+
+    is-path $parent.child-secure('foo/../bar'), $parent.child('bar'),
+        'resolved parent with resolving, non-existent child, with ../';
+
+    fails-like { $parent.child-secure('foo/../../bar') }, X::IO::NotAChild,
+        'resolved parent fails (given path is not a child, via child + ../)';
+}

S32-io/null-char.t

@@ -6,7 +6,7 @@ use Test::Util;
 # Tests for ensuring NUL byte is rejected from paths
 constant @nuls = ("\0foobar", "foo\0bar", "foobar\0", "\0foo\0bar\0");
 
-plan 5*@nuls;
+plan 7*@nuls;
 
 {
     temp $*CWD = make-temp-dir;
@@ -17,6 +17,9 @@ plan 5*@nuls;
         throws-like { chdir $nul          }, X::IO::Null, "&chdir $d";
         throws-like { $nul.IO             }, X::IO::Null, ".IO $d";
         throws-like { IO::Path.new: $nul  }, X::IO::Null, "IO::Path.new $d";
+        throws-like { $*CWD.child: $nul   }, X::IO::Null, ".child $d";
+        throws-like { $*CWD.child-secure: $nul }, X::IO::Null,
+            ".child-secure $d";
     }
 }