"bash" me all you want, but this is sweet. It turns the verbose output of Unity xUnit framework for C (yes, straight eff'n C) into JUnit results that Jenkins CI can eat.

unity_to_junit.pl

use strict;
use warnings;

my $fname = shift or die 'filename!';
open my $fh, $fname or die "Could not open $fname: $!";

print "<testsuite>\n";

foreach(grep /^ *(IGNORE_)?TEST/, <$fh>) {
  my ($status, $group, $test, $detail);
  $status = $group = $test = $detail = "";

  ($status, $group, $test)          = ($_ =~ m/(IGNORE)_TEST\(([^,]*), ([^)]*)\).*$/) or
  ($group, $test, $status)          = ($_ =~ m/TEST\(([^,]*), ([^)]*)\) *(PASS).*$/) or
  ($group, $test, $status, $detail) = ($_ =~ m/TEST\(([^,]*), ([^)]*)\)[^:]*:[^:]*:[^:]*:[^:]*:(FAIL):(.*$)/);

  print "  <testcase classname=\"$group\" name=\"$test\">\n";
  print "    <skipped></skipped>\n" if $status eq "IGNORE";
  print "    <failure>\n        <![CDATA[$detail]]>\n    </failure>\n" if $status eq "FAIL";
  print "  </testcase>\n";
}

print "</testsuite>\n";

unity_to_junit.sh

  #!/bin/bash
  
  #TODO: assert argument exists and is a file, etc.
  
  cat << END_OF_RESULTS
  <testsuite>
  $(
  cat $1 | grep -Ee "^ *(IGNORE_)?TEST" | while read line; do
    command=$(echo $line | \
              sed  \
              -e 's/IGNORE_TEST(\([^,]*\), \([^)]*\)).*$/group="\1"; test="\2"; status="IGNORE";/' \
              -e 's/TEST(\([^,]*\), \([^)]*\)) \(PASS\).*$/group="\1"; test="\2"; status="\3";/' \
              -e 's/TEST(\([^,]*\), \([^)]*\))[^:]*:\([^:]*\):\([^:]*\):\([^:]*\):\(FAIL\):\(.*$\)/group="\1"; test="\2"; status="\6"; detail="\7"/')
    eval "$command"
    echo "  <testcase classname=\"$group\" name=\"$test\">"
    [[ "$status" == "IGNORE" ]] && echo "    <skipped></skipped>"
    [[ "$status" == "FAIL" ]] && echo "    <failure>
        <![CDATA[
        $detail
        ]]>
      </failure>"
    echo "  </testcase>"
  done
  )
  </testsuite>
   
  END_OF_RESULTS

Input

Unity test run 1 of 1
TEST(Group1, test1) PASS
TEST(Group1, test2) PASS
TEST(Group2, test3) PASS
TEST(Group2, test4) PASS
TEST(Group3, test5)c:\path\to\sometests.c:51:TEST(Group3, test5):FAIL: Expected 2 Was 1

 -----------------------
 5 Tests 1 Failures 0 Ignored
 FAIL

Output

<testsuite>
  <testcase classname="Group1" name="test1">
  </testcase>
  <testcase classname="Group1" name="test2">
  </testcase>
  <testcase classname="Group2" name="test3">
  </testcase>
  <testcase classname="Group2" name="test4">
  </testcase>
  <testcase classname="Group3" name="test5">
    <failure>
      <![CDATA[
       Expected 2 Was 1
      ]]>
    </failure>
  </testcase>
</testsuite>

I added your file test in my fork

I added a perl implementation; surprisingly readable!