chore: Unreachable code is error (#2216)

cmake/Settings.cmake

@@ -16,6 +16,7 @@ set(COMPILER_FLAGS
     -Wnull-dereference
     -Wold-style-cast
     -Wpedantic
+    -Wunreachable-code
     -Wunused
     # FIXME: The following bunch are needed for gcc12 atm.
     -Wno-missing-requires

tests/integration/data/cassandra/BackendTests.cpp

@@ -1424,7 +1424,7 @@ TEST_F(BackendCassandraNodeMessageTest, UpdatingMessageKeepsItAlive)
 {
 #if defined(__APPLE__)
     GTEST_SKIP() << "Skipping test on Apple platform due to slow DB";
-#endif
+#else
     static boost::uuids::uuid const kUUID = generateUuid();
     static std::string const kUPDATED_MESSAGE = "updated message";
 
@@ -1442,4 +1442,5 @@ TEST_F(BackendCassandraNodeMessageTest, UpdatingMessageKeepsItAlive)
         EXPECT_EQ(uuid, kUUID);
         EXPECT_EQ(message, kUPDATED_MESSAGE);
     });
+#endif
 }