### Question:
GcpComputePlatform extends Platform implements SshBasedExperiment<GcpComputeInstanceContainer> { public String setTagsSafe (GcpComputeInstanceContainer container, List<String> newTags, String oldFingerprint) { Tags tagChangeRequest = Tags.newBuilder().addAllItems(newTags != null ? newTags : Collections.emptyList()). setFingerprint(oldFingerprint).build(); ProjectZoneInstanceName instance = getProjectZoneInstanceNameOfContainer(container, getProjectName()); return getInstanceClient().setTagsInstance(instance, tagChangeRequest).getSelfLink(); }  void setRoutableCIDRBlocks(Collection<String> routableCIDRBlocks); @Override ApiStatus getApiStatus(); @Override PlatformLevel getPlatformLevel(); @Override PlatformHealth getPlatformHealth(); Collection<Items> getIncludeFilter(); void setIncludeFilter(Map<String, String> includeFilter); Collection<Items> getExcludeFilter(); void setExcludeFilter(Map<String, String> excludeFilter); @Override boolean isContainerRecycled(Container container); String stopInstance(GcpComputeInstanceContainer container); ContainerHealth isContainerRunning(GcpComputeInstanceContainer gcpComputeInstanceContainer); String simulateMaintenance(GcpComputeInstanceContainer container); String setTags(GcpComputeInstanceContainer container, List<String> tags); String setTagsSafe(GcpComputeInstanceContainer container, List<String> newTags, String oldFingerprint); boolean isContainerGroupAtCapacity(GcpComputeInstanceContainer container); boolean checkTags(GcpComputeInstanceContainer container, List<String> expectedTags); void startInstance(GcpComputeInstanceContainer container); String restartContainer(GcpComputeInstanceContainer container); String getBestEndpoint(String privateIPAddress, String publicIPAddress); boolean isAddressRoutable(String privateIPAddress); String getLatestInstanceId(String instanceName, String zone); Fingerprint<List<String>> getFirewallTags(GcpComputeInstanceContainer container); void setProjectId(String projectId); @Override String getEndpoint(GcpComputeInstanceContainer container); @Override SSHCredentials getSshCredentials(GcpComputeInstanceContainer container); @Override String getRunningDirectory(); @Override void recycleContainer(GcpComputeInstanceContainer container); String recreateInstanceInInstanceGroup(GcpComputeInstanceContainer container); boolean isOperationComplete(String operationId);  }### Answer:
@Test public void setTagsSafe () { GcpComputeInstanceContainer container = GcpComputeInstanceContainer.builder() .withZone("my-datacenter") .withInstanceName("my-instance") .withUniqueIdentifier("1234567890") .build(); List<String> tags = List.of("new-tag"); String oldFingerprint = "old-fingerprint"; Tags actualTags = Tags.newBuilder().setFingerprint(oldFingerprint).addAllItems(tags).build(); ProjectZoneInstanceName instanceName = ProjectZoneInstanceName.of("1234567890", MY_AWESOME_PROJECT, "my-datacenter"); doReturn(Operation.newBuilder().setSelfLink("my-operation").build()).when(instanceClient) .setTagsInstance(instanceName, actualTags); assertEquals("my-operation", gcpComputePlatform.setTagsSafe(container, tags, oldFingerprint)); }