Não super elegante, mas aqui vai:
sed -ne 's/.*"test-summary".* \([0-9][0-9]* right [^&].*exceptions\) .*//p'
Por exemplo:
$ echo '<script>document.getElementById("test-summary").innerHTML = "<strong>Test Pages:</strong> 1 right, 0 wrong, 0 ignored, 0 exceptions ' | sed -ne 's/.*"test-summary".* \([0-9][0-9]* right,[^&].*exceptions\) .*//p'
1 right, 0 wrong, 0 ignored, 0 exceptions