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" });