package mock type Builder struct { BuildInvoked bool BuildFn func(name, path string) (image string, err error) } func NewBuilder() *Builder { return &Builder{ BuildFn: func(string, string) (string, error) { return "", nil }, } } func (i *Builder) Build(name, path string) (string, error) { i.BuildInvoked = true return i.BuildFn(name, path) }