You can use the below code to create a mock of ICacheEntry for IMemoryCache mock set up in Xunit:
Mock<IMemoryCache> mockObject = new Mock<IMemoryCache>();
var cachEntry = new Mock<ICacheEntry>();
mockObject.Setup(x => x.CreateEntry(It.IsAny<string>()))
.Returns(cachEntry.Object);
Namespaces used:
using Microsoft.Extensions.Caching.Memory;
using Moq;