We use a developer tree like src (contains the master-SLN and other code-stuff) build (contains tools to build assemblies, code-doku, ..) bin (central common output-folder for c#-compiler) Under src normally the <project>.nunit should lay. But this file then references the assembly in a schema like: <assembly path="..\bin\Debug\EsriDE.P... /> This gives an error by running nunit-console.exe: Could not load file or assembly 'EsriDE.PipelineManagement.... ......