public HealthCheck.Result runHealthCheck(String name) throws NoSuchElementException {
        final HealthCheck healthCheck = healthChecks.get(name);
        if (healthCheck == null) {
            throw new NoSuchElementException("No health check named " + name + " exists");
        }
        return healthCheck.execute();
    }
@Test
    public void doesNotRunNonexistentHealthChecks()  {
        try {
            registry.runHealthCheck("what");
            failBecauseExceptionWasNotThrown(NoSuchElementException.class);
        } catch (NoSuchElementException e) {
            assertThat(e.getMessage())
                .isEqualTo("No health check named what exists");
        }

    }