以下是您可以使用的两种方法:

Following are two approaches you could use:

// Directly test the middleware itself without setting up the pipeline
[Fact]
public async Task Approach1()
{
    // Arrange
    var httpContext = new DefaultHttpContext();
    var authMiddleware = new MyAuthMiddleware(next: (innerHttpContext) => Task.FromResult(0));

    // Act
    await authMiddleware.Invoke(httpContext);

    // Assert
    // Note that the User property on DefaultHttpContext is never null and so do
    // specific checks for the contents of the principal (ex: claims)
    Assert.NotNull(httpContext.User);
    var claims = httpContext.User.Claims;
    //todo: verify the claims
}

[Fact]
public async Task Approach2()
{
    // Arrange
    var server = TestServer.Create((app) =>
    {
        app.UseMiddleware<MyAuthMiddleware>();

        app.Run(async (httpContext) =>
        {
            if(httpContext.User != null)
            {
                await httpContext.Response.WriteAsync("Claims: "
                    + string.Join(
                        ",",
                        httpContext.User.Claims.Select(claim => string.Format("{0}:{1}", claim.Type, claim.Value))));
            }
        });
    });

    using (server)
    {
        // Act
        var response = await server.CreateClient().GetAsync("/");

        // Assert
        var actual = await response.Content.ReadAsStringAsync();
        Assert.Equal("Claims: ClaimType1:ClaimType1-value", actual);
    }
}