diff --git a/S32-io/io-path-cygwin.t b/S32-io/io-path-cygwin.t
index 11760cf768..3576a69c9d 100644
--- a/S32-io/io-path-cygwin.t
+++ b/S32-io/io-path-cygwin.t
@@ -2,7 +2,7 @@ use v6;
 use Test;
 # L<S32::IO/IO::Path>
 
-plan 51;
+plan 52;
 
 # Make sure we have a controlled environment
 my $*SPEC = IO::Spec::Cygwin;
@@ -82,3 +82,7 @@ is $numfile.succ.succ,    "foo/file03.txt", "succ x 2";
 is $numfile.pred,    "foo/file00.txt", "pred basic";
 is IO::Path::Unix.new("foo/()").succ, "foo/()", "succ only effects basename";
 is IO::Path::Unix.new("foo/()").succ, "foo/()", "pred only effects basename";
+
+# RT#128840
+isnt IO::Path::Cygwin.new('-a').absolute, '',
+    '.absolute on paths starting with `-` does not produce empty string';
diff --git a/S32-io/io-path-unix.t b/S32-io/io-path-unix.t
index c02a258234..b3d9bc0470 100644
--- a/S32-io/io-path-unix.t
+++ b/S32-io/io-path-unix.t
@@ -2,7 +2,7 @@ use v6;
 use Test;
 # L<S32::IO/IO::Path>
 
-plan 36;
+plan 37;
 
 # make sure we have a controlled environment here
 my $*SPEC = IO::Spec::Unix;
@@ -66,3 +66,7 @@ is $numfile.succ.succ, "foo/file03.txt", "succ x 2";
 is $numfile.pred,      "foo/file00.txt", "pred basic";
 is IO::Path::Unix.new("foo/()").succ, "foo/()", "succ only effects basename";
 is IO::Path::Unix.new("foo/()").succ, "foo/()", "pred only effects basename";
+
+# RT#128840
+isnt IO::Path::Unix.new("-a").absolute, '',
+    '.absolute on paths starting with `-` does not produce empty string';
diff --git a/S32-io/io-path-win.t b/S32-io/io-path-win.t
index 6eff5caaea..5ca604c4c1 100644
--- a/S32-io/io-path-win.t
+++ b/S32-io/io-path-win.t
@@ -2,7 +2,7 @@ use v6;
 use Test;
 # L<S32::IO/IO::Path>
 
-plan 50;
+plan 51;
 
 my $*SPEC = IO::Spec::Win32;  # .IO needs to have IO::Spec::Win32
 my $*CWD  = 'C:\\zip\\loc'.IO;
@@ -81,3 +81,7 @@ is $numfile.succ.succ,    "foo\\file03.txt", "succ x 2";
 is $numfile.pred,    "foo\\file00.txt", "pred basic";
 is IO::Path::Win32.new("foo\\()").succ, "foo\\()", "succ only effects basename";
 is IO::Path::Win32.new("foo\\()").succ, "foo\\()", "pred only effects basename";
+
+# RT#128840
+isnt IO::Path::Win32.new('-a').absolute, '',
+    '.absolute on paths starting with `-` does not produce empty string';