Singleton v. Bonnesen (1955) 131 Cal. App. 2d 327 affirmed judgment following an employer's demurrer where the plaintiff alleged injury to an employee within the course of employment but made no mention of workers' compensation insurance. ( Singleton v. Bonnesen, supra, 131 Cal. App. 2d at pp. 328-329.) Importantly, the Court of Appeal found it proper to presume that the employer complied with the law requiring its purchase of workers' compensation insurance. ( Id. at p. 331.) A plaintiff's action against an employer upon allegations of a work-related injury is barred unless the plaintiff also alleges that the employer has failed to secure the payment of workers' compensation through mandated insurance. (Ibid.)