diff --git a/test/language/expressions/cpp/LengthOfOperatorTest.cpp b/test/language/expressions/cpp/LengthOfOperatorTest.cpp
index f32e094..76d603f 100644
--- a/test/language/expressions/cpp/LengthOfOperatorTest.cpp
+++ b/test/language/expressions/cpp/LengthOfOperatorTest.cpp
@@ -67,7 +67,7 @@ TEST(LengthOfOperatorTest, getLengthOfVariableArray)
 
 TEST(LengthOfOperatorTest, getLengthOfFirstStrInArray)
 {
-    auto strArray = VectorType<StringType>{{StringType("€"), StringType("$")}};
+    auto strArray = VectorType<StringType>{"€", "$"};
     LengthOfFunctions data;
     data.strArray = strArray;
     ASSERT_EQ(3, strArray.at(0).size()); // check that it's length in bytes (UTF-8)
@@ -76,7 +76,7 @@ TEST(LengthOfOperatorTest, getLengthOfFirstStrInArray)
 
 TEST(LengthOfOperatorTest, getLengthOfFirstBytesInArray)
 {
-    auto bytesArray = VectorType<BytesType>{{{{0x00, 0x01}}, {{}}}};
+    auto bytesArray = VectorType<BytesType>{{0x00, 0x01}, {}};
     LengthOfFunctions data;
     data.bytesArray = bytesArray;
     ASSERT_EQ(bytesArray.at(0).size(), zserio::View(data).getLengthOfFirstBytesInArray());
@@ -92,13 +92,13 @@ TEST(LengthOfOperatorTest, literalLengthFieldDefault)
 TEST(LengthOfOperatorTest, writeRead)
 {
     LengthOfFunctions data;
-    data.fixedArray = VectorType<::zserio::UInt8>{{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09}};
+    data.fixedArray = VectorType<::zserio::UInt8>{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09};
     data.numElements = 3;
-    data.variableArray = VectorType<::zserio::UInt8>{{0x03, 0x02, 0x01}};
+    data.variableArray = VectorType<::zserio::UInt8>{0x03, 0x02, 0x01};
     data.strField = "longer than constant";
     data.bytesField = BytesType{{0x00, 0x01, 0x02}};
-    data.strArray = VectorType<StringType>();
-    data.bytesArray = VectorType<BytesType>();
+    data.strArray = VectorType<StringType>{"text1", "text2", "text3", "text4"};
+    data.bytesArray = VectorType<BytesType>{{0x01, 0x02}, {0x03, 0x04}};
 
     test_utils::writeReadTest(data);
 }