单元测试 - 组装加载失败

Question

I have a Visual studio project (containing NUnit tests) with Platform target: Any CPU (Debug and Release). This projects references a dll (Reference.dll) with following Configuration:

(from ILSpy)
// Architecture: AnyCPU (64-bit preferred)
// This assembly contains unmanaged code.
// Runtime: .NET 4.0

[assembly: CLSCompliant(true)]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyProduct("DotNet")]
[assembly: AssemblyTitle("DotNet")]
[assembly: AssemblyTrademark("")]
[assembly: ComVisible(false)]
[assembly: TargetFramework(".NETFramework,Version=v4.5", FrameworkDisplayName = ".NET Framework 4.5")]
[assembly: SecurityRules(SecurityRuleSet.Level1)]
[assembly: SecurityPermission(SecurityAction.RequestMinimum, UnmanagedCode = true)]
[assembly: SecurityPermission(SecurityAction.RequestMinimum, SkipVerification = true)]

Upon building the project, Tests.dll is generated with following configuration.

(from ILSpy)
// Architecture: AnyCPU (64-bit preferred)
// Runtime: .NET 4.0

[assembly: Debuggable(DebuggableAttribute.DebuggingModes.IgnoreSymbolStoreSequencePoints)]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyTrademark("")]
[assembly: CompilationRelaxations(8)]
[assembly: RuntimeCompatibility(WrapNonExceptionThrows = true)]
[assembly: ComVisible(false)]
[assembly: Guid("37AAB39F-D11B-4C7D-887C-A056A63177A3")]
[assembly: TargetFramework(".NETFramework,Version=v4.5", FrameworkDisplayName = ".NET Framework 4.5")]

I use Resharper to run the NUnit tests with following preferences:

Default platform architecture: Automatic based on test project's target platform

Default .NET framework version: Automatic based on test projet's target platform

When a test case is executed and any method from Reference.dll is used, I get following exception: System.BadImageFormatException: Could not load file or assembly '' or one of its dependencies. An attempt was made to load a program with an incorrect format.

When I change the target platform of Tests.dll to x86 , it works. Could anyone explain me why Any CPU for both the platforms is not working.

Answer 1

This seems to be failing because the assembly that is being tested (not the one with your tests), is 32 bit. If the test project is set to AnyCPU, it will run as 64 bit, and fail to load the assembly under test.

You need to set your test project to have the same bit-ness as the assembly under test, or its dependencies. ReSharper only looks at the test assembly when deciding if it should run as 32 or 64 bit.