it('has one error', () => {
            expect(errors.length).toBe(1);
        });

        it('error text belongs to failed rule', () => {
            expect(errors[0]).toContain('fake reason');
        });
    });

    const makeFailingRule = (reason) => {
        return () => {
            return { passed: false, reason: reason };
        };
    };

    const makePassingRule = () => () => {
        return { passed: true, reason: '' };
    };
});