Тъкмо започнах писането на задачите, и още при първата ми гърми със непознат error?:
 

Compiled file is missing. Compiler output: Microsoft (R) Build Engine version 15.5.180.51428 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

  Restoring packages for ...\BookShop.csproj...
  Restoring packages for ...\BookShop.Initializer.csproj...
  Restoring packages for ...\BookShop.Data.csproj...
  Restoring packages for ...\NUnitLiteConsoleApp.csproj...
  Restoring packages for ...\BookShop.Models.csproj...
  Generating MSBuild file ...\BookShop.Models.csproj.nuget.g.props.
  Generating MSBuild file ...\BookShop.Models.csproj.nuget.g.targets.
  Restore completed in 354.38 ms for ...\BookShop.Models.csproj.
  Generating MSBuild file ...\BookShop.csproj.nuget.g.props.
  Generating MSBuild file ...\BookShop.csproj.nuget.g.targets.
  Generating MSBuild file ...\BookShop.Initializer.csproj.nuget.g.props.
  Generating MSBuild file ...\BookShop.Initializer.csproj.nuget.g.targets.
  Restore completed in 657.96 ms for ...\BookShop.csproj.
  Restore completed in 660.03 ms for ...\BookShop.Initializer.csproj.
  Generating MSBuild file ...\BookShop.Data.csproj.nuget.g.props.
  Generating MSBuild file ...\BookShop.Data.csproj.nuget.g.targets.
  Restore completed in 669.85 ms for ...\BookShop.Data.csproj.
  Generating MSBuild file ...\NUnitLiteConsoleApp.csproj.nuget.g.props.
  Generating MSBuild file ...\NUnitLiteConsoleApp.csproj.nuget.g.targets.
  Restore completed in 769.55 ms for ...\NUnitLiteConsoleApp.csproj.
  BookShop.Models -> ...\BookShop.Models.dll
  BookShop.Data -> ...\BookShop.Data.dll
  BookShop.Initializer -> ...\BookShop.Initializer.dll
  BookShop -> ...\BookShop.dll
CSC : warning CS8032: An instance of analyzer Microsoft.EntityFrameworkCore.RawSqlStringInjectionDiagnosticAnalyzer cannot be created from ...\Microsoft.EntityFrameworkCore.Analyzers.dll : Could not load file or assembly 'Microsoft.CodeAnalysis, Version=2.8.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.. [...\NUnitLiteConsoleApp.csproj]
Test_001.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_004.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_Open_001.cs(115,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_002.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_003.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]

Build FAILED.

CSC : warning CS8032: An instance of analyzer Microsoft.EntityFrameworkCore.RawSqlStringInjectionDiagnosticAnalyzer cannot be created from ...\Microsoft.EntityFrameworkCore.Analyzers.dll : Could not load file or assembly 'Microsoft.CodeAnalysis, Version=2.8.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.. [...\NUnitLiteConsoleApp.csproj]
Test_001.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_004.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_Open_001.cs(115,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_002.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
Test_003.cs(42,79): error CS0023: Operator '.' cannot be applied to operand of type 'void' [...\NUnitLiteConsoleApp.csproj]
    1 Warning(s)
    5 Error(s)

ако някой може да обясни какво точно иска ще съм доволен :D