Implement new optional test to catch validate fix

test/language/optional_members/CMakeLists.txt

@@ -19,6 +19,7 @@ add_custom_test(optional_members
         optional_members_zs
     SOURCES
         ${CMAKE_CURRENT_SOURCE_DIR}/cpp/AutoOptionalTest.cpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/cpp/OptionalComplexExpressionTest.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/cpp/OptionalRecursionTest.cpp
     GENERATED_SOURCES
         ${GENERATED_SOURCES}

test/language/optional_members/ClangTidySuppressions.txt

@@ -2,3 +2,5 @@ bugprone-exception-escape:gen/optional_members/optional_recursion/Block.cpp
 bugprone-exception-escape:gen/optional_members/optional_recursion/Block.h
 
 misc-no-recursion # reports also tested_release
+
+google-explicit-constructor:gen/optional_members/optional_complex_expression/Permission.h

test/language/optional_members/cpp/OptionalComplexExpressionTest.cpp

@@ -0,0 +1,35 @@
+#include "gtest/gtest.h"
+#include "optional_members/optional_complex_expression/Container.h"
+#include "test_utils/TestUtility.h"
+
+namespace optional_members
+{
+namespace optional_complex_expression
+{
+
+class OptionalComplexExpressionTest : public ::testing::Test
+{
+protected:
+    static constexpr zserio::BitSize CONTAINER_WITHOUT_OPTIONAL_BIT_SIZE = 5;
+    static constexpr zserio::BitSize CONTAINER_WITH_OPTIONAL_BIT_SIZE = 9;
+    static constexpr zserio::UInt4 EXTRA_DATA_VALUE = 0x0F;
+};
+
+TEST_F(OptionalComplexExpressionTest, withoutOptional)
+{
+    Container data{Permission::Values::READ, {}};
+    ASSERT_EQ(CONTAINER_WITHOUT_OPTIONAL_BIT_SIZE, zserio::detail::bitSizeOf(zserio::View<Container>(data)));
+
+    test_utils::writeReadTest(data);
+}
+
+TEST_F(OptionalComplexExpressionTest, withOptional)
+{
+    Container data{Permission::Values::WRITE, EXTRA_DATA_VALUE};
+    ASSERT_EQ(CONTAINER_WITH_OPTIONAL_BIT_SIZE, zserio::detail::bitSizeOf(zserio::View<Container>(data)));
+
+    test_utils::writeReadTest(data);
+}
+
+} // namespace optional_complex_expression
+} // namespace optional_members