diff --git a/test/DataFilters.Expressions.UnitTests/DataFilters.Expressions.UnitTests.csproj b/test/DataFilters.Expressions.UnitTests/DataFilters.Expressions.UnitTests.csproj
index a6185b18..5e6c0ee1 100644
--- a/test/DataFilters.Expressions.UnitTests/DataFilters.Expressions.UnitTests.csproj
+++ b/test/DataFilters.Expressions.UnitTests/DataFilters.Expressions.UnitTests.csproj
@@ -24,6 +24,7 @@
         <PackageReference Include="NodaTime.Testing" Version="3.2.2"/>
     </ItemGroup>
     <ItemGroup>
+      <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="8.0.1" />
         <ProjectReference Include="..\..\src\Datafilters.Expressions\DataFilters.Expressions.csproj"/>
     </ItemGroup>