Getting Could not load file or assembly 'System.Core, Version=4.0.0.0..' While doing unit testing in asp.net core with moq

问题

I am having a very simple unit test. when I run the test I get the exception Could not load file or assembly 'Could not load file or assembly 'System.Core, Version=4.0.0.0..' This error started appearing after I added "Microsoft.NETCore.Portable.Compatibility": "1.0.1" in my Project.json file. But it is required or else I cannot use lambda Expression in unit testing.

There is no compile time error in my unit test.I am sure there is nothing wrong with my test it is the project.json file missing something . below is my test.

Mock<RegistrationManager> manager = new Mock<RegistrationManager>();
            Mock<RegistrationModel> model = new Mock<RegistrationModel>();
            var value = manager.Setup(a => a.GetDataFieldValuesForModel(model.Object, CommandType.next)).ReturnsAsync(new RegistrationModel { hasError = false, FormId="123",LeadId="345" });


{
  "version": "0.1.0-*",
  "dependencies": {
    "Moq": "4.5.22",
    "xunit": "2.2.0-beta2-build3300",
    "dotnet-test-xunit": "2.2.0-preview2-build1029",
    "IntegraPay.Domain": {
      "version": "1.0.0-*",
      "target": "project"
    },
    "Integrapay.RegistrationApplication": {
      "version": "",
      "target": "project"
    },
    "Microsoft.NETCore.Portable.Compatibility": "1.0.1"
  },
  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "net451"
      ],
      "dependencies": {
        "Microsoft.NETCore.App": {
          "type": "platform",
          "version": "1.0.0"
        }
      }
    }
  },
  "testRunner": "xunit"
}

回答1:

Had the same issue.

Solved it by several changes:

Changed dependency from Moq to Moq.netcore (you also need to add custom nuget feed "https://www.myget.org/F/aspnet-contrib/api/v3/index.json", found it in http://dotnetliberty.com/index.php/2016/02/22/moq-on-net-core/)
Removed imported dnx451 (net451 in your case), this answer helped me a lot: https://stackoverflow.com/a/39856247/1546582
Removed link to compatibility project (you don't need it with moq.netcore)
Add reference to System.Diagnostics.TraceSource (cause it isn't referenced, but needed for some reason)

My final project.json looks like:

{
  "version": "1.0.0-*",

  "dependencies": {
    "NUnit": "3.5.0",
    "dotnet-test-nunit": "3.4.0-beta-2",
    "MyTestingProject": "1.0.0-*",
    "Moq.netcore": "4.4.0-beta8",
    "System.Diagnostics.TraceSource": "4.0.0" 
  },
  "testRunner": "nunit",

  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "netcoreapp1.0",
        "dnxcore50"
      ],
      "dependencies": {
        "Microsoft.NETCore.App": {
          "version": "1.0.1",
          "type": "platform"
        }
      }
    }
  }
}

来源：https://stackoverflow.com/questions/39843015/getting-could-not-load-file-or-assembly-system-core-version-4-0-0-0-while-d

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