Closes #32

tests/README.md

@@ -295,6 +295,25 @@ Attribute changes were verified with `qmake6 ../dbc.pro`, `make -j4`, and
 passed. The standalone C++17 tree test also passed. The existing named
 comma-decimal C locale test skipped because the locale is not installed.
 
+## Long signal definitions
+
+`longSignalDefinitions` reproduces the former stack overflow with a 50,000-character
+unit string. Both parser APIs are exercised with long units, signal names,
+receivers, decimal numbers, and a list of 10,001 receivers. Valid input must parse
+without truncating units; malformed input (including missing quotes, delimiters,
+receiver separators, numeric suffixes, overflow, and trailing receiver commas)
+must return an empty database and an `InvalidStatement` diagnostic at the signal's
+source line, or throw a source-located error through `ParseFile()`.
+These cases run as part of the existing parser target and sanitizer builds.
+
+Verified with Qt 6.8.2 in separate Release and ASan/UBSan builds, both with
+`CONFIG+=dbc_qt`: `make check` passed 2,409 core QtTest checks, seven model checks,
+and the qmake tree test in each build. The named comma-decimal C locale test
+skipped because the required locale is not installed. The sanitizer run used
+`ASAN_OPTIONS=detect_leaks=0:halt_on_error=1` and `UBSAN_OPTIONS=halt_on_error=1`;
+address and undefined-behavior checks passed, while leak checking was disabled
+because of the environment's previously documented ptrace restriction.
+
 ## Extended validation
 
 `attributeNumbers` checks signed 64-bit limits, leading plus signs, decimal HEX