Testing usage of comms::option::VarLength and comms::option::NumValueSerOffset together.

Author: arobenko

test/Fields2.th

@@ -64,6 +64,7 @@ public:
     void test36();
     void test37();
     void test38();
+    void test39();
 
 private:
     template <typename TField>
@@ -2253,6 +2254,35 @@ void FieldsTestSuite2::test38()
     // field.setBitValue(1, true); // Must fail compilation
 }
 
+void FieldsTestSuite2::test39()
+{
+    typedef comms::field::IntValue<
+        comms::Field<BigEndianOpt>,
+        std::int16_t,
+        comms::option::VarLength<1, 4>,
+        comms::option::NumValueSerOffset<-1900>
+    > Field;
+
+    static_assert(!Field::isVersionDependent(), "Invalid version dependency assumption");
+
+    static const char Buf[] = {
+        static_cast<char>(0x81), 0x00,
+    };
+    static const std::size_t BufSize = std::extent<decltype(Buf)>::value;
+    auto field = readWriteField<Field>(Buf, BufSize);
+
+    TS_ASSERT_EQUALS(field.length(), 2);
+    TS_ASSERT_EQUALS(field.value(), 2028);
+    TS_ASSERT(field.valid());
+
+    field.value() = 2030;
+    static const char ExpectedBuf[] = {
+        static_cast<char>(0x81), 0x02,
+    };
+    const std::size_t ExpectedBufSize = std::extent<decltype(ExpectedBuf)>::value;
+    writeReadField(field, ExpectedBuf, ExpectedBufSize);
+}
+
 template <typename TField>
 void FieldsTestSuite2::writeField(
     const TField& field,