diff --git a/src/tests/unittests/validation/RenderPipelineValidationTests.cpp b/src/tests/unittests/validation/RenderPipelineValidationTests.cpp
index c0e9e69fa7..c64bca6529 100644
--- a/src/tests/unittests/validation/RenderPipelineValidationTests.cpp
+++ b/src/tests/unittests/validation/RenderPipelineValidationTests.cpp
@@ -1334,7 +1334,8 @@ TEST_F(InterStageVariableMatchingValidationTest, DifferentTypeAtSameLocation) {
         std::string interfaceDeclaration;
         {
             std::ostringstream sstream;
-            sstream << "struct A { @location(0) a: " << kTypes[i] << ";" << std::endl;
+            sstream << "struct A { @location(0) @interpolate(flat) a: " << kTypes[i] << ";"
+                    << std::endl;
             interfaceDeclaration = sstream.str();
         }
         {