CakeBuild: Get failed to install tool 'NUnit.ConsoleRunner' - nunit-console

Question

I used CakeBuild to build and test my Xamarin Portable Class Library.
In the build.cake script I defined that I want to use the NUnit-Console to run my testcases. So I do
#tool nuget:?package=NUnit.ConsoleRunner
Unfortunatelly I get the following error when I run the Cake script.
Preparing to run build script...
VERBOSE: Restoring tools from NuGet...
VERBOSE: Feeds used:
C:\Users\bergkar\.nuget\packages\
All packages listed in C:\dev\Xamarin\fleetboard-core-library\tools\packages.config are already installed.
Running build script...
Analyzing build script...
Processing build script...
Installing tools...
Unable to find package 'NUnit.ConsoleRunner'
NuGet exited with 1
Could not find any relevant files for tool 'NUnit.ConsoleRunner'. Perhaps you need an include parameter?
Error: Failed to install tool 'NUnit.ConsoleRunner'.
When I add a specific version I want to use like below then everything works fine.
#tool nuget:?package=NUnit.ConsoleRunner&version=3.7.0
Can someone tell me why it is not working without the version stuff?
With ".\build.ps1 -Verbosity Diagnostic" I get the following output:
Preparing to run build script...
Running build script...
Module directory does not exist.
Analyzing build script...
Analyzing C:/dev/Xamarin/fleetboard-core-library/build.cake...
Processing build script...
Installing tools...
Installing NuGet package NUnit.ConsoleRunner...
Executing: "C:/dev/Xamarin/fleetboard-core-library/tools/nuget.exe" install "NUnit.ConsoleRunner" -OutputDirectory "C:/d
ev/Xamarin/fleetboard-core-library/tools" -ExcludeVersion -NonInteractive
Unable to find package 'NUnit.ConsoleRunner'
NuGet exited with 1
Feeds used:
Output:
Feeds used:
Could not find any relevant files for tool 'NUnit.ConsoleRunner'. Perhaps you need an include parameter?
Error: Cake.Core.CakeException: Failed to install tool 'NUnit.ConsoleRunner'.
at Cake.Core.Scripting.ScriptProcessor.InstallTools(ScriptAnalyzerResult analyzerResult, DirectoryPath installPath)
at Cake.Core.Scripting.ScriptRunner.Run(IScriptHost host, FilePath scriptPath, IDictionary`2 arguments)
at Cake.Commands.BuildCommand.Execute(CakeOptions options)
at Cake.CakeApplication.Run(CakeOptions options)
at Cake.Program.Main()

Answer 1

Now I found my problem and solved it.
The problem was that the NuGet.exe did not has a source feed which points to a public nuget source like "https://api.nuget.org/v3/index.json".
This was because my default NuGet.conf in under "C:\Users\YOUR_USER_HOME\AppData\Roaming\NuGet" had no packageSource defined. So Nuget just knows the local nuget package cache under "C:\Users\YOUR_USER_HOME.nuget\packages" and this did not include the specified package.
So after I added a packageSource in "C:\Users\YOUR_USER_HOME\AppData\Roaming\NuGet\NuGet.Conf" everything works fine.
Another way can be to add a new NuGet.Conf beside your build.ps1 file which contains all package sources you need for CakeBuild and your Xamarin project.
The following page explains how Nuget finds its configuration. Maybe this is helpful to understand the mechanism NuGet uses to find its configuration:
https://learn.microsoft.com/en-us/nuget/consume-packages/configuring-nuget-behavior