lua: pattern character sets [...] and [^...] +3 tests; tests reach deeper code

lib/lua/test.sh

@@ -986,6 +986,14 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1902)
 (eval "(lua-eval-ast \"if tonumber('99', 8) == nil then return 1 else return 0 end\")")
 
+;; ── Pattern character sets [...] ──────────────────────────────
+(epoch 1910)
+(eval "(lua-eval-ast \"return string.match(\\\"hello123\\\", \\\"[a-z]+\\\")\")")
+(epoch 1911)
+(eval "(lua-eval-ast \"return string.match(\\\"hello123\\\", \\\"[0-9]+\\\")\")")
+(epoch 1912)
+(eval "(lua-eval-ast \"return string.match(\\\"abc\\\", \\\"[^a]+\\\")\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 60 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1495,6 +1503,11 @@ check 1900 "tonumber('1010', 2)"            '10'
 check 1901 "tonumber('FF', 16)"             '255'
 check 1902 "tonumber('99', 8) → nil"        '1'
 
+# ── Pattern character sets [...] ─────────────────────────────
+check 1910 "[a-z]+ on hello123"             '"hello"'
+check 1911 "[0-9]+ on hello123"             '"123"'
+check 1912 "[^a]+ on abc"                   '"bc"'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL Lua-on-SX tests passed"