String getAvailabilityZone() {
        return gcpMetadataApi.currentZone();
    }
@Test
    public void getAvailabilityZone() {
        // given
        given(gcpMetadataApi.currentZone()).willReturn(ZONE_1);
        GcpConfig gcpConfig = GcpConfig.builder().build();
        GcpClient gcpClient = new GcpClient(gcpMetadataApi, gcpComputeApi, gcpAuthenticator, gcpConfig);

        // when
        String result = gcpClient.getAvailabilityZone();

        // then
        assertEquals(ZONE_1, result);
    }