pose: NullReferenceException in Pose.Helpers.StubHelper.GetMatchingShimIndex

Using Pose in a fairly complex test I’ve been getting this exception. It seems to be trying to find a shim for method(s) that haven’t been shimmed. Unfortunately I’ve not been able to reproduce this in a simple example and can’t post the full code from my product.

The test project is using an in-memory ASP.NET Core server (https://docs.microsoft.com/en-us/aspnet/core/testing/integration-testing) and the method I’m shimming is called from the Controller, not directly from the unit test itself. I expect this is the underlying problem as I’m calling PoseContext.Isolate from the “client” and expecting it to maintain that isolation on the “server” side.

Anyway, I’m posting this anyway in case you have any suggestions.

Unit test:

#if !NET462
        [Fact]
        public void When_person_exists_in_db()
        {
            var sqlMapperShim = Shim.Replace(() => SqlMapper.QueryAsync<Applicant>(Is.A<IDbConnection>(), Is.A<CommandDefinition>()))
                .With(
                    delegate (IDbConnection dbConnection, CommandDefinition commandDefinition)
                    {
                        return Task.FromResult(SqlMapper.Query<Applicant>(dbConnection, commandDefinition));
                    });

            Default<ApplicantListViewModel> response = null;

            PoseContext.Isolate(() =>
            {
                var httpResponse = this.Read($"organisations/{TestConstants.OrganisationIdentifier}/applicants");
                response = httpResponse.Content.ReadAsAsync<Default<ApplicantListViewModel>>().Result;
            },
            sqlMapperShim);

            // Assert
            response.ShouldNotBe(null);
        }
#endif

Test results:

Test run for C:\Code\MyCompany\MyProduct\test\MyCompany.MyProduct.Specs\bin\Debug\netcoreapp2.0\MyCompany.MyProduct.Specs.dll(.NETCoreApp,Version=v2.0)
Microsoft (R) Test Execution Command Line Tool Version 15.3.0-preview-20170628-02
Copyright (c) Microsoft Corporation.  All rights reserved.

Starting test execution, please wait...
[xUnit.net 00:00:01.4649449]   Discovering: MyCompany.MyProduct.Specs
[xUnit.net 00:00:01.5546231]   Discovered:  MyCompany.MyProduct.Specs
[xUnit.net 00:00:01.5617069]   Starting:    MyCompany.MyProduct.Specs
[xUnit.net 00:00:53.7768297]     MyCompany.MyProduct.Specs.ApplicantsSpecs.ApplicantListSpecs.When_person_exists_in_db2 [FAIL]
[xUnit.net 00:00:53.7786980]       System.NullReferenceException : Object reference not set to an instance of an object.
[xUnit.net 00:00:53.7800539]       Stack Trace:
[xUnit.net 00:00:53.7811621]         C:\Code\MyCompany\MyProduct\test\MyCompany.MyProduct.Specs\Pose\IL\MethodRewriter.cs(27,0): at Pose.IL.MethodRewriter.Rewrite()
[xUnit.net 00:00:53.7813452]            at stub_System.Net.Http.Headers.HttpHeaders_ParseRawHeaderValues(HttpHeaders , String , HeaderStoreItemInfo , Boolean , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7814211]            at dynamic_System.Net.Http.Headers.HttpHeaders_AddHeaders(HttpHeaders , HttpHeaders )
[xUnit.net 00:00:53.7814574]            at stub_System.Net.Http.Headers.HttpHeaders_AddHeaders(HttpHeaders , HttpHeaders , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7814902]            at dynamic_System.Net.Http.Headers.HttpRequestHeaders_AddHeaders(HttpRequestHeaders , HttpHeaders )
[xUnit.net 00:00:53.7815276]            at stub_System.Net.Http.Headers.HttpHeaders_AddHeaders(HttpHeaders , HttpHeaders , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7815669]            at stub_System.Net.Http.HttpClient_PrepareRequestMessage(HttpClient , HttpRequestMessage , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7816352]            at dynamic_System.Net.Http.HttpClient_SendAsync(HttpClient , HttpRequestMessage , HttpCompletionOption , CancellationToken )
[xUnit.net 00:00:53.7816805]            at stub_System.Net.Http.HttpClient_SendAsync(HttpClient , HttpRequestMessage , HttpCompletionOption , CancellationToken , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7817409]            at dynamic_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption , CancellationToken )
[xUnit.net 00:00:53.7817783]            at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption , CancellationToken , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7818927]            at dynamic_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption )
[xUnit.net 00:00:53.7819275]            at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7820015]            at dynamic_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri )
[xUnit.net 00:00:53.7820570]            at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7821121]            at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , String , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7821604]            at dynamic_MyCompany.MyProduct.Specs.BehavesLikeApi_Read(BehavesLikeApi , String , Dictionary`2 , Dictionary`2 )
[xUnit.net 00:00:53.7822409]            at stub_MyCompany.MyProduct.Specs.BehavesLikeApi_Read(BehavesLikeApi , String , Dictionary`2 , Dictionary`2 , RuntimeMethodHandle , RuntimeTypeHandle )
[xUnit.net 00:00:53.7823764]            at dynamic_MyCompany.MyProduct.Specs.ApplicantsSpecs.ApplicantListSpecs+<>c__DisplayClass3_0_<When_person_exists_in_db2>b__1(<>c__DisplayClass3_0 )
Failed   MyCompany.MyProduct.Specs.ApplicantsSpecs.ApplicantListSpecs.When_person_exists_in_db2
Error Message:
 System.NullReferenceException : Object reference not set to an instance of an object.
Stack Trace:
   at Pose.IL.MethodRewriter.Rewrite() in C:\Code\MyCompany\MyProduct\test\MyCompany.MyProduct.Specs\Pose\IL\MethodRewriter.cs:line 27
   at stub_System.Net.Http.Headers.HttpHeaders_ParseRawHeaderValues(HttpHeaders , String , HeaderStoreItemInfo , Boolean , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_System.Net.Http.Headers.HttpHeaders_AddHeaders(HttpHeaders , HttpHeaders )
   at stub_System.Net.Http.Headers.HttpHeaders_AddHeaders(HttpHeaders , HttpHeaders , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_System.Net.Http.Headers.HttpRequestHeaders_AddHeaders(HttpRequestHeaders , HttpHeaders )
   at stub_System.Net.Http.Headers.HttpHeaders_AddHeaders(HttpHeaders , HttpHeaders , RuntimeMethodHandle , RuntimeTypeHandle )
   at stub_System.Net.Http.HttpClient_PrepareRequestMessage(HttpClient , HttpRequestMessage , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_System.Net.Http.HttpClient_SendAsync(HttpClient , HttpRequestMessage , HttpCompletionOption , CancellationToken )
   at stub_System.Net.Http.HttpClient_SendAsync(HttpClient , HttpRequestMessage , HttpCompletionOption , CancellationToken , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption , CancellationToken )
   at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption , CancellationToken , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption )
   at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , HttpCompletionOption , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri )
   at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , Uri , RuntimeMethodHandle , RuntimeTypeHandle )
   at stub_System.Net.Http.HttpClient_GetAsync(HttpClient , String , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_MyCompany.MyProduct.Specs.BehavesLikeApi_Read(BehavesLikeApi , String , Dictionary`2 , Dictionary`2 )
   at stub_MyCompany.MyProduct.Specs.BehavesLikeApi_Read(BehavesLikeApi , String , Dictionary`2 , Dictionary`2 , RuntimeMethodHandle , RuntimeTypeHandle )
   at dynamic_MyCompany.MyProduct.Specs.ApplicantsSpecs.ApplicantListSpecs+<>c__DisplayClass3_0_<When_person_exists_in_db2>b__1(<>c__DisplayClass3_0 )
[xUnit.net 00:01:10.9337665]   Finished:    MyCompany.MyProduct.Specs

Total tests: 47. Passed: 46. Failed: 1. Skipped: 0.
Test Run Failed.

About this issue

Original URL
State: open
Created 7 years ago
Comments: 15 (6 by maintainers)

Most upvoted comments

I’ve noticed that Assert statements tend to break Pose. I’m currently looking into it, but in the meantime you can do this instead:

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
namespace Pose.Tests.Fails
{
    [TestClass]
    public class ShimFails
    {
        public class MyClass
        {
            public int MyProperty { get; set; }
        }

        [TestMethod]
        [ExpectedException(typeof(NullReferenceException))]
        public void ShimConstructor()
        {
            Shim ctorShim = Shim.Replace(() => new MyClass())
                .With(() => new MyClass { MyProperty = 10 });
            
            int prop = 0;

            PoseContext.Isolate(() =>
            {
                prop = new MyClass().MyProperty;
            }, ctorShim);

            // this line breaks the Shim
            Assert.AreEqual(10, prop);
        }
    }
}

tonerdo on Mar 24, 2018