public void TestApplyDiff(ModuleSet starting, Diff diff, ModuleSet expected)
{
ModuleSet updated = starting.ApplyDiff(diff);
Assert.Equal(expected.Modules.Count, updated.Modules.Count);
foreach (KeyValuePair <string, IModule> module in expected.Modules)
{
Assert.True(updated.TryGetModule(module.Key, out IModule updatedMod));
Assert.Equal(module.Value, updatedMod);
}
}