Error when packaging plugin

Your MockTests.Build.cs exists? The Object inside is called MockTests?

using UnrealBuildTool;

public class MockTests : ModuleRules
{
	public MockTests(ReadOnlyTargetRules Target)
	: base(Target)
    {
		PrivateIncludePaths.AddRange(
			new string[] {
				"MockTests/Private"
			}
		);
		
		PrivateDependencyModuleNames.AddRange(
			new string[]
            {
				"Core",
				"CoreUObject",
				"Engine"
			}
		);
	}
}

change

PrivateDependencyModuleNames.AddRange(new string[] { "MockTests" });