diff --git a/test-linuxcnc-rs274-native.sh b/test-linuxcnc-rs274-native.sh
index 0e76828..6b6ec7c 100755
--- a/test-linuxcnc-rs274-native.sh
+++ b/test-linuxcnc-rs274-native.sh
@@ -300,6 +300,8 @@ done
 # numbers, and non-leading ATAN argument slashes.
 bad_character_error_cases=(
     "linuxcnc_bad_character_bang_error|Bad character '!' used"
+    "linuxcnc_commented_percent_error|Bad character '%' used"
+    "linuxcnc_mid_program_percent_error|Bad character '%' used"
     "linuxcnc_bad_character_middle_n_word_error|Bad character 'n' used"
     "linuxcnc_comment_prefixed_n_word_error|Bad character 'n' used"
     "linuxcnc_comment_prefixed_spaced_n_word_error|Bad character 'n' used"
@@ -328,11 +330,14 @@ done
 # Source basis: LinuxCNC src/emc/rs274ngc/interp_read.cc read_text()
 # rejects EOF without the matching percent/program end and overlong file
 # lines; read_n_number() rejects malformed N-line numbers through
-# read_integer_unsigned().
+# read_integer_unsigned(); src/emc/rs274ngc/interp_internal.cc
+# close_and_downcase() rejects unclosed and nested parenthesis comments.
 read_text_error_cases=(
     "linuxcnc_file_ended_no_program_end_error|File ended with no percent sign"
     "linuxcnc_file_ended_no_percent_error|File ended with no percent sign"
     "linuxcnc_bad_n_number_format_error|Bad format unsigned integer"
+    "linuxcnc_unclosed_comment_error|Unclosed comment found"
+    "linuxcnc_nested_comment_error|Nested comment found"
 )
 for case in "${read_text_error_cases[@]}"; do
     fixture=${case%%|*}