Closes #33

tests/README.md

@@ -99,7 +99,7 @@ line numbers for skipped syntax and immediate/deferred errors; warnings precedin
 an error are retained, and failed parses return an empty database. Common headers
 and namespace symbol lists stay quiet. Tests also check file-open errors, fresh
 parse sessions, and compatibility with the legacy throwing API.
-The diagnostic audit also covers 13 unsupported-statement variants, all namespace
+The diagnostic audit also covers 11 unsupported-statement variants, all namespace
 termination forms, CRLF and missing final newlines, relative paths with spaces,
 first-error stopping, deferred diagnostic ordering, duplicate definitions/values,
 selector ranges, overlaps, and preservation of supported decoding and metadata.
@@ -295,6 +295,30 @@ 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.
 
+## Unsupported signal value types
+
+`unsupportedSignalValueTypes` verifies that both parser APIs reject `SIG_VALTYPE_`
+declarations with `UnsupportedSignalType`, the original file path and physical
+line, and an empty database. Cases include float32/float64, declarations before
+signal definitions, extended IDs, tabs/CRLF, no final newline, type 0, unknown
+types, and malformed declarations. Prior warnings are retained; `SIG_VALTYPE_`
+symbols inside `NS_` lists remain quiet.
+
+The pipeline suite checks the IEEE 754 bytes for float32 and float64 `1.0`.
+Adding a type declaration must prevent publication of an integer definition,
+so building from the error result cannot produce a valid decoded signal. The
+same payloads still decode to exact integers when defined only by supported
+`SG_` statements. New cases are included in the existing qmake targets.
+
+Verified with Qt 6.8.2 in separate Release and ASan/UBSan builds with
+`CONFIG+=dbc_qt`: each passed 2,420 core QtTest checks, seven model checks, and
+the qmake tree test. One named-locale case skipped because its locale is
+unavailable. ASan/UBSan used fatal errors and `detect_leaks=0` because of the
+previously documented ptrace restriction. The separately built demo was checked
+with float32 and float64 declarations (exit 2, source-located error, no decode
+output), a supported integer definition (exit 0), and an unknown extension
+(exit 0 with a visible warning).
+
 ## Long signal definitions
 
 `longSignalDefinitions` reproduces the former stack overflow with a 50,000-character