PredicateBuilder确实返回所有结果，并且可以'；我找不到罪魁祸首

我正在尝试实现PredicateBuilder，并创建了一个简单的测试。我目前正在使用PredicateBuilderDelegate，因为我正在针对List 进行测试

问题是，当我运行测试时，我没有"筛选"包含相同元素的记录和集合，我不明白为什么会发生这种情况。

FakeEntity类：

public class FakeEntity {
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public static Func<FakeEntity, bool> NotDeleted() {
        var predicate = PredicateBuilderDelegate.True<FakeEntity>();
        predicate.And(e => !e.IsDeleted);
        return predicate;
    }
}

测试：

[TestClass]
public class PredicateBuilderTest {
    [TestMethod]
    public void Test() {
        var collection = new List<FakeEntity>() { new FakeEntity { IsDeleted = true }, new FakeEntity { IsDeleted = false } };
        var result = collection.Where(FakeEntity.NotDeleted()).ToList();
        CollectionAssert.AreNotEquivalent(collection, result); // FAIL!
        Assert.IsTrue(result.Count() == 1); // FAIL !!
    }
}

PredicateBuilderDelegate:

public static class PredicateBuilderDelegate {
    public static Func<T, bool> True<T>() { return f => true; }
    public static Func<T, bool> False<T>() { return f => false; }
    public static Func<T, bool> Or<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) || expr2(t);
    }
    public static Func<T, bool> And<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) && expr2(t);
    }
}