diff --git a/t/t7008-grep-binary.sh b/t/t7008-grep-binary.sh
index 20370d6e0c..615e7e0162 100755
--- a/t/t7008-grep-binary.sh
+++ b/t/t7008-grep-binary.sh
@@ -22,6 +22,18 @@ nul_match () {
 			printf '$pattern' | q_to_nul >f &&
 			test_must_fail git grep -f f $flags a
 		"
+	elif test "$matches" = T1
+	then
+		test_expect_failure "git grep -f f $flags '$pattern_human' a" "
+			printf '$pattern' | q_to_nul >f &&
+			git grep -f f $flags a
+		"
+	elif test "$matches" = T0
+	then
+		test_expect_failure "git grep -f f $flags '$pattern_human' a" "
+			printf '$pattern' | q_to_nul >f &&
+			test_must_fail git grep -f f $flags a
+		"
 	else
 		test_expect_success "PANIC: Test framework error. Unknown matches value $matches" 'false'
 	fi
@@ -98,6 +110,65 @@ nul_match 1 '-Fi' 'YQf'
 nul_match 0 '-Fi' 'YQx'
 nul_match 1 '' 'yQf'
 nul_match 0 '' 'yQx'
+nul_match 1 '' 'æQð'
+nul_match 1 '-F' 'eQm[*]c'
+nul_match 1 '-Fi' 'EQM[*]C'
+
+# Regex patterns that would match but shouldn't with -F
+nul_match 0 '-F' 'yQ[f]'
+nul_match 0 '-F' '[y]Qf'
+nul_match 0 '-Fi' 'YQ[F]'
+nul_match 0 '-Fi' '[Y]QF'
+nul_match 0 '-F' 'æQ[ð]'
+nul_match 0 '-F' '[æ]Qð'
+nul_match 0 '-Fi' 'ÆQ[Ð]'
+nul_match 0 '-Fi' '[Æ]QÐ'
+
+# kwset is disabled on -i & non-ASCII. No way to match non-ASCII \0
+# patterns case-insensitively.
+nul_match T1 '-i' 'ÆQÐ'
+
+# \0 implicitly disables regexes. This is an undocumented internal
+# limitation.
+nul_match T1 '' 'yQ[f]'
+nul_match T1 '' '[y]Qf'
+nul_match T1 '-i' 'YQ[F]'
+nul_match T1 '-i' '[Y]Qf'
+nul_match T1 '' 'æQ[ð]'
+nul_match T1 '' '[æ]Qð'
+nul_match T1 '-i' 'ÆQ[Ð]'
+
+# ... because of \0 implicitly disabling regexes regexes that
+# should/shouldn't match don't do the right thing.
+nul_match T1 '' 'eQm.*cQ'
+nul_match T1 '-i' 'EQM.*cQ'
+nul_match T0 '' 'eQm[*]c'
+nul_match T0 '-i' 'EQM[*]C'
+
+# Due to the REG_STARTEND extension when kwset() is disabled on -i &
+# non-ASCII the string will be matched in its entirety, but the
+# pattern will be cut off at the first \0.
+nul_match 0 '-i' 'NOMATCHQð'
+nul_match T0 '-i' '[Æ]QNOMATCH'
+nul_match T0 '-i' '[æ]QNOMATCH'
+# Matches, but for the wrong reasons, just stops at [æ]
+nul_match 1 '-i' '[Æ]Qð'
+nul_match 1 '-i' '[æ]Qð'
+
+# Ensure that the matcher doesn't regress to something that stops at
+# \0
+nul_match 0 '-F' 'yQ[f]'
+nul_match 0 '-Fi' 'YQ[F]'
+nul_match 0 '' 'yQNOMATCH'
+nul_match 0 '' 'QNOMATCH'
+nul_match 0 '-i' 'YQNOMATCH'
+nul_match 0 '-i' 'QNOMATCH'
+nul_match 0 '-F' 'æQ[ð]'
+nul_match 0 '-Fi' 'ÆQ[Ð]'
+nul_match 0 '' 'yQNÓMATCH'
+nul_match 0 '' 'QNÓMATCH'
+nul_match 0 '-i' 'YQNÓMATCH'
+nul_match 0 '-i' 'QNÓMATCH'
 
 test_expect_success 'grep respects binary diff attribute' '
 	echo text >t &&