it('has no errors', () => {
            expect(errors.length).toBe(0);
        });
    });

    describe('with a failing and a passing rule', () => {
        let fakeRulePass, fakeRuleFail, errors;

        beforeEach(() => {
            fakeRulePass = () => ({  passed: true, reason: 'fake success'  });
            fakeRuleFail = () => ({  passed: false, reason: 'fake reason'  });
            verifier.addRule(fakeRulePass);
            verifier.addRule(fakeRuleFail);
            errors = verifier.verify('any value');
        });

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

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