diff --git a/parser/tst/Makefile b/parser/tst/Makefile
index 040779fa8..dafb05e21 100644
--- a/parser/tst/Makefile
+++ b/parser/tst/Makefile
@@ -23,7 +23,7 @@ tests: error_output caching minimize equality parser_sanity
 GEN_TRANS_DIRS=simple_tests/generated_x/ simple_tests/generated_perms_leading/ simple_tests/generated_perms_safe/ simple_tests/generated_dbus
 
 gen_xtrans: $(GEN_TRANS_DIRS)
-	./gen-xtrans.pl
+	./gen-xtrans.py
 
 $(GEN_TRANS_DIRS):
 	mkdir $@
diff --git a/parser/tst/gen-xtrans.pl b/parser/tst/gen-xtrans.pl
deleted file mode 100755
index 8cf077f4b..000000000
--- a/parser/tst/gen-xtrans.pl
+++ /dev/null
@@ -1,235 +0,0 @@
-#!/usr/bin/perl
-
-use strict;
-use Locale::gettext;
-use POSIX;
-
-setlocale(LC_MESSAGES, "");
-
-my $prefix="simple_tests/generated_x";
-my $prefix_leading="simple_tests/generated_perms_leading";
-my $prefix_safe="simple_tests/generated_perms_safe";
-
-my @trans_types = ("p", "P", "c", "C", "u", "i");
-my @modifiers = ("i", "u");
-my %trans_modifiers = (
-    "p" => \@modifiers,
-    "P" => \@modifiers,
-    "c" => \@modifiers,
-    "C" => \@modifiers,
-    );
-
-my @targets = ("", "target", "target2");
-my @null_target = ("");
-
-my %named_trans = (
-    "p" => \@targets,
-    "P" => \@targets,
-    "c" => \@targets,
-    "C" => \@targets,
-    "u" => \@null_target,
-    "i" => \@null_target,
-    );
-
-my %safe_map = (
-    "p" => "unsafe",
-    "P" => "safe",
-    "c" => "unsafe",
-    "C" => "safe",
-    "u" => "",
-    "i" => "",
-    );
-
-my %invert_safe = (
-    "safe" => "unsafe",
-    "unsafe" => "safe",
-    );
-
-# audit qualifier disabled for now it really shouldn't affect the conflict
-# test but it may be worth checking every once in awhile
-#my @qualifiers = ("", "owner", "audit", "audit owner");
-my @qualifiers = ("", "owner");
-
-my $count = 0;
-
-gen_conflicting_x();
-gen_overlap_re_exact();
-gen_dominate_re_re();
-gen_ambiguous_re_re();
-gen_leading_perms("exact", "/bin/cat", "/bin/cat");
-gen_leading_perms("exact-re", "/bin/*", "/bin/*");
-gen_leading_perms("overlap", "/*", "/bin/cat");
-gen_leading_perms("dominate", "/**", "/*");
-gen_leading_perms("ambiguous", "/a*", "/*b");
-gen_safe_perms("exact", "PASS", "", "/bin/cat", "/bin/cat");
-gen_safe_perms("exact-re", "PASS", "", "/bin/*", "/bin/*");
-gen_safe_perms("overlap", "PASS", "", "/*", "/bin/cat");
-gen_safe_perms("dominate", "PASS", "", "/**", "/*");
-gen_safe_perms("ambiguous", "PASS", "", "/a*", "/*b");
-gen_safe_perms("exact", "FAIL", "inv", "/bin/cat", "/bin/cat");
-gen_safe_perms("exact-re", "FAIL", "inv", "/bin/*", "/bin/*");
-gen_safe_perms("overlap", "PASS", "inv", "/*", "/bin/cat");
-gen_safe_perms("dominate", "FAIL", "inv", "/**", "/*");
-gen_safe_perms("ambiguous", "FAIL", "inv", "/a*", "/*b");
-
-print "Generated $count xtransition interaction tests\n";
-
-sub gen_list {
-    my @output;
-    foreach my $trans (@trans_types) {
-	if ($trans_modifiers{$trans}) {
-	    foreach my $mod (@{$trans_modifiers{$trans}}) {
-		push @output, "${trans}${mod}x";
-	    }
-	}
-	push @output, "${trans}x";
-    }
-    return @output;
-}
-
-sub print_rule($$$$$$) {
-    my ($file, $leading, $qual, $name, $perm, $target) = @_;
-    if ($leading) {
-	print $file "\t${qual} ${perm} ${name}";
-    } else {
-	print $file "\t${qual} ${name} ${perm}";
-    }
-    if ($target ne "") {
-	print $file " -> $target";
-    }
-    print $file ",\n";
-}
-
-sub gen_file($$$$$$$$$$$$) {
-    my ($name, $xres, $leading1, $qual1, $rule1, $perm1, $target1, $leading2, $qual2, $rule2, $perm2, $target2) = @_;
-
-#    print "$xres $rule1 $perm1 $target1 $rule2 $perm2 $target2\n";
-
-    my $file;
-    unless (open $file, ">$name") {
-	print("couldn't open $name\n");
-	exit 1;
-    }
-
-    print $file "#\n";
-    print $file "#=DESCRIPTION ${name}\n";
-    print $file "#=EXRESULT ${xres}\n";
-    print $file "#\n";
-    print $file "/usr/bin/foo {\n";
-    print_rule($file, $leading1, $qual1, $rule1, $perm1, $target1);
-    print_rule($file, $leading2, $qual2, $rule2, $perm2, $target2);
-    print $file "}\n";
-    close($file);
-
-    $count++;
-}
-
-#NOTE: currently we don't do px to cx, or cx to px conversion
-#      so
-# /foo {
-#    /* px -> /foo//bar,
-#    /* cx -> bar,
-#
-# will conflict
-#
-#NOTE: conflict tests don't tests leading permissions or using unsafe keywords
-#      It is assumed that there are extra tests to verify 1 to 1 coorispondance
-sub gen_files($$$$) {
-    my ($name, $rule1, $rule2, $default) = @_;
-
-    my @perms = gen_list();
-
-#    print "@perms\n";
-
-    foreach my $i (@perms) {
-	foreach my $t (@{$named_trans{substr($i, 0, 1)}}) {
-	    foreach my $q (@qualifiers) {
-		foreach my $j (@perms) {
-		    foreach my $u (@{$named_trans{substr($j, 0, 1)}}) {
-			foreach my $r (@qualifiers) {
-			    my $file="${prefix}/${name}-$q$i$t-$r$j$u.sd";
-#		    print "$file\n";
-
-		    #override failures when transitions are the same
-			    my $xres = ${default};
-			    if ($i eq $j && $t eq $u) {
-				$xres = "PASS";
-			    }
-
-
-#		    print "foo $xres $rule1 $i $t $rule2 $j $u\n";
-			    gen_file($file, $xres, 0, $q, $rule1, $i, $t, 0, $r, $rule2, $j, $u);
-			}
-		    }
-		}
-	    }
-	}
-    }
-
-}
-
-sub gen_conflicting_x {
-    gen_files("conflict", "/bin/cat", "/bin/cat", "FAIL");
-}
-
-sub gen_overlap_re_exact {
-
-    gen_files("exact", "/bin/cat", "/bin/*", "PASS");
-}
-
-# we currently don't support this, once supported change to "PASS"
-sub gen_dominate_re_re {
-    gen_files("dominate", "/bin/*", "/bin/**", "FAIL");
-}
-
-sub gen_ambiguous_re_re {
-    gen_files("ambiguous", "/bin/a*", "/bin/*b", "FAIL");
-}
-
-
-# test that rules that lead with permissions don't conflict with
-# the same rule using trailing permissions.
-sub gen_leading_perms($$$) {
-    my ($name, $rule1, $rule2) = @_;
-
-    my @perms = gen_list();
-
-    foreach my $i (@perms) {
-	foreach my $t (@{$named_trans{substr($i, 0, 1)}}) {
-	    foreach my $q (@qualifiers) {
-		my $file="${prefix_leading}/${name}-$q$i$t.sd";
-#		    print "$file\n";
-
-		gen_file($file, "PASS", 0, $q, $rule1, $i, $t, 1, $q, $rule2, $i, $t);
-	    }
-	}
-    }
-}
-
-# test for rules with leading safe or unsafe keywords.
-# check they are equivalent to their counter part,
-# or if $invert that they properly conflict with their counterpart
-sub gen_safe_perms($$$$$) {
-    my ($name, $xres, $invert, $rule1, $rule2) = @_;
-
-    my @perms = gen_list();
-
-    foreach my $i (@perms) {
-	foreach my $t (@{$named_trans{substr($i, 0, 1)}}) {
-	    foreach my $q (@qualifiers) {
-		my $qual = $safe_map{substr($i, 0, 1)};
-		if ($invert) {
-		    $qual = $invert_safe{$qual};
-		}
-		if (! $invert || $qual) {
-		    my $file="${prefix_safe}/${name}-$invert-$q${qual}-rule-$i$t.sd";
-#		    print "$file\n";
-		    gen_file($file, $xres, 0, "$q $qual", $rule1, $i, $t, 1, $q, $rule2, $i, $t);
-		    $file="${prefix_safe}/${name}-$invert-$q$qual${i}-rule-$t.sd";
-		    gen_file($file, $xres, 0, $q, $rule1, $i, $t, 1, "$q $qual", $rule2, $i, $t);
-		}
-
-	    }
-	}
-    }
-}
diff --git a/parser/tst/gen-xtrans.py b/parser/tst/gen-xtrans.py
new file mode 100755
index 000000000..139fe1d8b
--- /dev/null
+++ b/parser/tst/gen-xtrans.py
@@ -0,0 +1,219 @@
+#!/usr/bin/python3
+# ------------------------------------------------------------------
+#
+#   Copyright (C) 2010-2011 Canonical Ltd.
+#   Copyright (C) 2020 Christian Boltz
+#
+#   This program is free software; you can redistribute it and/or
+#   modify it under the terms of version 2 of the GNU General Public
+#   License published by the Free Software Foundation.
+#
+# ------------------------------------------------------------------
+
+from testlib import write_file
+
+prefix = "simple_tests/generated_x"
+prefix_leading = "simple_tests/generated_perms_leading"
+prefix_safe = "simple_tests/generated_perms_safe"
+
+trans_types = ("p", "P", "c", "C", "u", "i")
+modifiers = ("i", "u")
+trans_modifiers = {
+    "p": modifiers,
+    "P": modifiers,
+    "c": modifiers,
+    "C": modifiers,
+}
+
+targets = ("", "target", "target2")
+# null_target uses "_" instead of "" because "" gets skipped in some for loops. Replace with "" when actually using the value.
+null_target = ("_")
+
+named_trans = {
+    "p": targets,
+    "P": targets,
+    "c": targets,
+    "C": targets,
+    "u": null_target,
+    "i": null_target,
+}
+
+safe_map = {
+    "p": "unsafe",
+    "P": "safe",
+    "c": "unsafe",
+    "C": "safe",
+    "u": "",
+    "i": "",
+}
+
+invert_safe = {
+    "safe": "unsafe",
+    "unsafe": "safe",
+    '': '',
+}
+
+# audit qualifier disabled for now it really shouldn't affect the conflict
+# test but it may be worth checking every once in awhile
+# qualifiers = ("", "owner", "audit", "audit owner")
+qualifiers = ("", "owner")
+
+count = 0
+
+def gen_list():
+    output = []
+    for trans in trans_types:
+        if trans in trans_modifiers:
+            for mod in trans_modifiers[trans]:
+                output.append("%s%sx" % (trans, mod))
+
+        output.append("%sx" % trans)
+
+    return output
+
+def test_gen_list():
+    ''' test if gen_list returns the expected output '''
+
+    expected = "pix pux px Pix Pux Px cix cux cx Cix Cux Cx ux ix".split()
+    actual = gen_list()
+
+    if actual != expected:
+        raise Exception("gen_list produced unexpected result, expected %s, got %s" % (expected, actual))
+
+def build_rule(leading, qual, name, perm, target):
+    rule = ''
+
+    if leading:
+        rule += "\t%s %s %s" % (qual, perm, name)
+    else:
+        rule += "\t%s %s %s" % (qual, name, perm)
+
+    if target != "":
+        rule += " -> %s" % target
+
+    rule += ",\n"
+
+    return rule
+
+def gen_file (name, xres, leading1, qual1, rule1, perm1, target1, leading2, qual2, rule2, perm2, target2):
+    global count
+    count += 1
+
+    content = ''
+    content += "#\n"
+    content += "#=DESCRIPTION %s\n" % name
+    content += "#=EXRESULT %s\n" % xres
+    content += "#\n"
+    content += "/usr/bin/foo {\n"
+    content += build_rule(leading1, qual1, rule1, perm1, target1)
+    content += build_rule(leading2, qual2, rule2, perm2, target2)
+    content += "}\n"
+
+    write_file('', name, content)
+
+
+# NOTE: currently we don't do px to cx, or cx to px conversion
+#      so
+# /foo {
+#    /* px -> /foo//bar,
+#    /* cx -> bar,
+#
+# will conflict
+#
+# NOTE: conflict tests don't tests leading permissions or using unsafe keywords
+#      It is assumed that there are extra tests to verify 1 to 1 coorispondance
+def gen_files(name, rule1, rule2, default):
+    perms = gen_list()
+
+    for i in perms:
+        for t in named_trans[i[0]]:
+            if t == '_':
+                t = ''
+            for q in qualifiers:
+                for j in perms:
+                    for u in named_trans[j[0]]:
+                        if u == '_':
+                            u = ''
+                        for r in qualifiers:
+                            file = prefix + '/' + name + '-' + q + i + t + '-' + r + j + u + '.sd'
+
+                            # override failures when transitions are the same
+                            xres = default
+                            if (i == j and t == u):
+                                xres = "PASS"
+
+                            gen_file(file, xres, 0, q, rule1, i, t, 0, r, rule2, j, u)
+
+def gen_conflicting_x():
+    gen_files("conflict", "/bin/cat", "/bin/cat", "FAIL")
+
+def gen_overlap_re_exact():
+    gen_files("exact", "/bin/cat", "/bin/*", "PASS")
+
+# we currently don't support this, once supported change to "PASS"
+def gen_dominate_re_re():
+    gen_files("dominate", "/bin/*", "/bin/**", "FAIL")
+
+def gen_ambiguous_re_re():
+    gen_files("ambiguous", "/bin/a*", "/bin/*b", "FAIL")
+
+
+# test that rules that lead with permissions don't conflict with
+# the same rule using trailing permissions.
+def gen_leading_perms (name, rule1, rule2):
+    perms = gen_list()
+
+    for i in perms:
+        for t in named_trans[i[0]]:
+            if t == '_':
+                t = ''
+            for q in qualifiers:
+                file = prefix_leading + '/' + name + '-' + q + i + t + ".sd"
+                gen_file(file, "PASS", 0, q, rule1, i, t, 1, q, rule2, i, t)
+
+# test for rules with leading safe or unsafe keywords.
+# check they are equivalent to their counter part,
+# or if $invert that they properly conflict with their counterpart
+def gen_safe_perms(name, xres, invert, rule1, rule2):
+    perms = gen_list()
+
+    for i in perms:
+        for t in named_trans[i[0]]:
+            if t == '_':
+                t = ''
+            for q in qualifiers:
+                qual = safe_map[i[0]]
+                if invert:
+                    qual = invert_safe[qual]
+
+                if (not invert or qual):
+                    file = prefix_safe + '/' + name + '-' + invert + '-' + q + qual + '-' + 'rule-' + i + t + '.sd'
+                    gen_file(file, xres, 0, '%s %s' % (q, qual), rule1, i, t, 1, q, rule2, i, t)
+
+                    file = prefix_safe + '/' + name + '-' + invert + '-' + q + qual + i + '-' + 'rule-' + t + '.sd'
+                    gen_file(file, xres, 0, q, rule1, i, t, 1, '%s %s' % (q, qual), rule2, i, t)
+
+
+test_gen_list()
+
+gen_conflicting_x()
+gen_overlap_re_exact()
+gen_dominate_re_re()
+gen_ambiguous_re_re()
+gen_leading_perms("exact", "/bin/cat", "/bin/cat")
+gen_leading_perms("exact-re", "/bin/*", "/bin/*")
+gen_leading_perms("overlap", "/*", "/bin/cat")
+gen_leading_perms("dominate", "/**", "/*")
+gen_leading_perms("ambiguous", "/a*", "/*b")
+gen_safe_perms("exact", "PASS", "", "/bin/cat", "/bin/cat")
+gen_safe_perms("exact-re", "PASS", "", "/bin/*", "/bin/*")
+gen_safe_perms("overlap", "PASS", "", "/*", "/bin/cat")
+gen_safe_perms("dominate", "PASS", "", "/**", "/*")
+gen_safe_perms("ambiguous", "PASS", "", "/a*", "/*b")
+gen_safe_perms("exact", "FAIL", "inv", "/bin/cat", "/bin/cat")
+gen_safe_perms("exact-re", "FAIL", "inv", "/bin/*", "/bin/*")
+gen_safe_perms("overlap", "PASS", "inv", "/*", "/bin/cat")
+gen_safe_perms("dominate", "FAIL", "inv", "/**", "/*")
+gen_safe_perms("ambiguous", "FAIL", "inv", "/a*", "/*b")
+
+print ("Generated %s xtransition interaction tests" % count)