open62541/tests/server/check_subscription_events.c

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <open62541/client_config_default.h>
#include <open62541/client_subscriptions.h>
#include <open62541/server.h>
#include <open62541/server_config_default.h>

#include "server/ua_server_internal.h"
#include "server/ua_services.h"
#include "server/ua_subscription.h"

#include <check.h>

#include "testing_clock.h"
#include "thread_wrapper.h"

#ifdef UA_ENABLE_SUBSCRIPTIONS_EVENTS

static UA_Server *server;
static size_t serverIterations;
static UA_Boolean running;
static THREAD_HANDLE server_thread;
static MUTEX_HANDLE serverMutex;

UA_Client *client;

static UA_UInt32 subscriptionId;
static UA_UInt32 monitoredItemId;
static UA_NodeId eventType;
static size_t nSelectClauses = 4;
static UA_Boolean notificationReceived;
static UA_Boolean overflowNotificationReceived;
static UA_SimpleAttributeOperand *selectClauses;

UA_Double publishingInterval = 500.0;

static void
addNewEventType(void) {
    UA_ObjectTypeAttributes attr = UA_ObjectTypeAttributes_default;
    attr.displayName = UA_LOCALIZEDTEXT_ALLOC("en-US", "SimpleEventType");
    attr.description = UA_LOCALIZEDTEXT_ALLOC("en-US", "The simple event type we created");

    UA_Server_addObjectTypeNode(server, UA_NODEID_NULL,
                                UA_NODEID_NUMERIC(0, UA_NS0ID_BASEEVENTTYPE),
                                UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE),
                                UA_QUALIFIEDNAME(0, "SimpleEventType"),
                                attr, NULL, &eventType);
    UA_LocalizedText_deleteMembers(&attr.displayName);
    UA_LocalizedText_deleteMembers(&attr.description);
}

static void
setupSelectClauses(void) {
    /* Check for severity (set manually), message (set manually), eventType
     * (automatic) and sourceNode (automatic) */
    selectClauses = (UA_SimpleAttributeOperand *)
            UA_Array_new(nSelectClauses, &UA_TYPES[UA_TYPES_SIMPLEATTRIBUTEOPERAND]);
    if(!selectClauses)
        return;

    for(size_t i = 0; i < nSelectClauses; ++i) {
        UA_SimpleAttributeOperand_init(&selectClauses[i]);
        selectClauses[i].typeDefinitionId = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEEVENTTYPE);
        selectClauses[i].browsePathSize = 1;
        selectClauses[i].attributeId = UA_ATTRIBUTEID_VALUE;
        selectClauses[i].browsePath = (UA_QualifiedName *)
                UA_Array_new(selectClauses[i].browsePathSize, &UA_TYPES[UA_TYPES_QUALIFIEDNAME]);
        if(!selectClauses[i].browsePathSize) {
            UA_Array_delete(selectClauses, nSelectClauses, &UA_TYPES[UA_TYPES_SIMPLEATTRIBUTEOPERAND]);
        }
    }

    selectClauses[0].browsePath[0] = UA_QUALIFIEDNAME_ALLOC(0, "Severity");
    selectClauses[1].browsePath[0] = UA_QUALIFIEDNAME_ALLOC(0, "Message");
    selectClauses[2].browsePath[0] = UA_QUALIFIEDNAME_ALLOC(0, "EventType");
    selectClauses[3].browsePath[0] = UA_QUALIFIEDNAME_ALLOC(0, "SourceNode");
}

static void
handler_events_simple(UA_Client *lclient, UA_UInt32 subId, void *subContext,
                      UA_UInt32 monId, void *monContext,
                      size_t nEventFields, UA_Variant *eventFields) {
    UA_Boolean foundSeverity = UA_FALSE;
    UA_Boolean foundMessage = UA_FALSE;
    UA_Boolean foundType = UA_FALSE;
    UA_Boolean foundSource = UA_FALSE;
    ck_assert_uint_eq(*(UA_UInt32 *) monContext, monitoredItemId);
    ck_assert_uint_eq(nEventFields, nSelectClauses);
    // check all event fields
    for(size_t i = 0; i < nEventFields; i++) {
        // find out which attribute of the event is being looked at
        if(UA_Variant_hasScalarType(&eventFields[i], &UA_TYPES[UA_TYPES_UINT16])) {
            // Severity
            ck_assert_uint_eq(*((UA_UInt16 *) (eventFields[i].data)), 1000);
            foundSeverity = UA_TRUE;
        } else if(UA_Variant_hasScalarType(&eventFields[i], &UA_TYPES[UA_TYPES_LOCALIZEDTEXT])) {
            // Message
            UA_LocalizedText comp = UA_LOCALIZEDTEXT("en-US", "Generated Event");
            ck_assert(UA_String_equal(&((UA_LocalizedText *) eventFields[i].data)->locale, &comp.locale));
            ck_assert(UA_String_equal(&((UA_LocalizedText *) eventFields[i].data)->text, &comp.text));
            foundMessage = UA_TRUE;
        } else if(UA_Variant_hasScalarType(&eventFields[i], &UA_TYPES[UA_TYPES_NODEID])) {
            // either SourceNode or EventType
            UA_NodeId serverId = UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER);
            if(UA_NodeId_equal((UA_NodeId *) eventFields[i].data, &eventType)) {
                // EventType
                foundType = UA_TRUE;
            } else if(UA_NodeId_equal((UA_NodeId *) eventFields[i].data, &serverId)) {
                // SourceNode
                foundSource = UA_TRUE;
            } else {
                ck_assert_msg(UA_FALSE, "NodeId doesn't match");
            }
        } else {
            ck_assert_msg(UA_FALSE, "Field doesn't match");
        }
    }
    ck_assert_uint_eq(foundMessage, UA_TRUE);
    ck_assert_uint_eq(foundSeverity, UA_TRUE);
    ck_assert_uint_eq(foundType, UA_TRUE);
    ck_assert_uint_eq(foundSource, UA_TRUE);
    notificationReceived = true;
}

// create a subscription and add a monitored item to it
static void
setupSubscription(void) {
    // Create subscription
    UA_CreateSubscriptionRequest request = UA_CreateSubscriptionRequest_default();
    UA_CreateSubscriptionResponse response =
        UA_Client_Subscriptions_create(client, request, NULL, NULL, NULL);
    subscriptionId = response.subscriptionId;
}

static void
removeSubscription(void) {
    UA_DeleteSubscriptionsRequest deleteSubscriptionsRequest;
    UA_DeleteSubscriptionsRequest_init(&deleteSubscriptionsRequest);
    UA_UInt32 removeId = subscriptionId;
    deleteSubscriptionsRequest.subscriptionIdsSize = 1;
    deleteSubscriptionsRequest.subscriptionIds = &removeId;

    UA_DeleteSubscriptionsResponse deleteSubscriptionsResponse;
    UA_DeleteSubscriptionsResponse_init(&deleteSubscriptionsResponse);

    Service_DeleteSubscriptions(server, &server->adminSession, &deleteSubscriptionsRequest,
                                &deleteSubscriptionsResponse);
    UA_DeleteSubscriptionsResponse_deleteMembers(&deleteSubscriptionsResponse);
}

static void serverMutexLock(void) {
    if (!(MUTEX_LOCK(serverMutex))) {
        fprintf(stderr, "Mutex cannot be locked.\n");
        exit(1);
    }
}

static void serverMutexUnlock(void) {
    if (!(MUTEX_UNLOCK(serverMutex))) {
        fprintf(stderr, "Mutex cannot be unlocked.\n");
        exit(1);
    }
}

THREAD_CALLBACK(serverloop) {
    while (running) {
        serverMutexLock();
        UA_Server_run_iterate(server, false);
        serverIterations++;
        serverMutexUnlock();
    }
    return 0;
}

static void
sleepUntilAnswer(UA_Double sleepMs) {
    UA_fakeSleep((UA_UInt32)sleepMs);
    serverMutexLock();
    size_t oldIterations = serverIterations;
    size_t newIterations;
    serverMutexUnlock();
    while(true) {
        serverMutexLock();
        newIterations = serverIterations;
        serverMutexUnlock();
        if(oldIterations != newIterations)
            return;
        UA_realSleep(1);
    }
}

static void
setup(void) {
    if (!MUTEX_INIT(serverMutex)) {
        fprintf(stderr, "Server mutex was not created correctly.");
        exit(1);
    }
    running = true;

    server = UA_Server_new();
    UA_ServerConfig *config = UA_Server_getConfig(server);
    UA_ServerConfig_setDefault(config);

    config->maxPublishReqPerSession = 5;
    UA_Server_run_startup(server);

    addNewEventType();
    setupSelectClauses();
    THREAD_CREATE(server_thread, serverloop);

    client = UA_Client_new();
    UA_ClientConfig_setDefault(UA_Client_getConfig(client));

    UA_StatusCode retval = UA_Client_connect(client, "opc.tcp://localhost:4840");
    if(retval != UA_STATUSCODE_GOOD) {
        fprintf(stderr, "Client can not connect to opc.tcp://localhost:4840. %s",
                UA_StatusCode_name(retval));
        exit(1);
    }
    setupSubscription();

    sleepUntilAnswer(publishingInterval + 100);
}

static void
teardown(void) {
    running = false;
    THREAD_JOIN(server_thread);
    removeSubscription();
    UA_Server_run_shutdown(server);
    UA_Server_delete(server);
    UA_Array_delete(selectClauses, nSelectClauses, &UA_TYPES[UA_TYPES_SIMPLEATTRIBUTEOPERAND]);

    UA_Client_disconnect(client);
    UA_Client_delete(client);
    if (!MUTEX_DESTROY(serverMutex)) {
        fprintf(stderr, "Server mutex was not destroyed correctly.");
        exit(1);
    }
}

static UA_StatusCode
triggerEventLocked(const UA_NodeId eventNodeId, const UA_NodeId origin,
                   UA_ByteString *outEventId, const UA_Boolean deleteEventNode) {
    serverMutexLock();
    UA_StatusCode retval = UA_Server_triggerEvent(server, eventNodeId, origin,
                                                  outEventId, deleteEventNode);
    serverMutexUnlock();
    return retval;
}

static UA_StatusCode
eventSetup(UA_NodeId *eventNodeId) {
    UA_StatusCode retval;
    serverMutexLock();
    retval = UA_Server_createEvent(server, eventType, eventNodeId);
    serverMutexUnlock();
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    // add a severity to the event
    UA_Variant value;
    UA_RelativePathElement rpe;
    UA_RelativePathElement_init(&rpe);
    rpe.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASPROPERTY);
    rpe.isInverse = false;
    rpe.includeSubtypes = false;
    UA_BrowsePath bp;
    UA_BrowsePath_init(&bp);
    bp.startingNode = *eventNodeId;
    bp.relativePath.elementsSize = 1;
    bp.relativePath.elements = &rpe;
    rpe.targetName = UA_QUALIFIEDNAME(0, "Severity");
    serverMutexLock();
    UA_BrowsePathResult bpr = UA_Server_translateBrowsePathToNodeIds(server, &bp);
    serverMutexUnlock();
    ck_assert_uint_eq(bpr.statusCode, UA_STATUSCODE_GOOD);
    // number with no special meaning
    UA_UInt16 eventSeverity = 1000;
    UA_Variant_setScalar(&value, &eventSeverity, &UA_TYPES[UA_TYPES_UINT16]);
    serverMutexLock();
    retval = UA_Server_writeValue(server, bpr.targets[0].targetId.nodeId, value);
    serverMutexUnlock();
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    UA_BrowsePathResult_deleteMembers(&bpr);

    //add a message to the event
    rpe.targetName = UA_QUALIFIEDNAME(0, "Message");
    serverMutexLock();
    bpr = UA_Server_translateBrowsePathToNodeIds(server, &bp);
    serverMutexUnlock();
    ck_assert_uint_eq(bpr.statusCode, UA_STATUSCODE_GOOD);
    UA_LocalizedText message = UA_LOCALIZEDTEXT("en-US", "Generated Event");
    UA_Variant_setScalar(&value, &message, &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
    serverMutexLock();
    retval = UA_Server_writeValue(server, bpr.targets[0].targetId.nodeId, value);
    serverMutexUnlock();
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    UA_BrowsePathResult_deleteMembers(&bpr);

    return retval;
}

static UA_MonitoredItemCreateResult
addMonitoredItem(UA_Client_EventNotificationCallback handler, bool setFilter) {
    UA_MonitoredItemCreateRequest item;
    UA_MonitoredItemCreateRequest_init(&item);
    item.itemToMonitor.nodeId = UA_NODEID_NUMERIC(0, 2253); // Root->Objects->Server
    item.itemToMonitor.attributeId = UA_ATTRIBUTEID_EVENTNOTIFIER;
    item.monitoringMode = UA_MONITORINGMODE_REPORTING;

    UA_EventFilter filter;
    UA_EventFilter_init(&filter);
    filter.selectClauses = selectClauses;
    filter.selectClausesSize = nSelectClauses;

    if (setFilter) {
        item.requestedParameters.filter.encoding = UA_EXTENSIONOBJECT_DECODED;
        item.requestedParameters.filter.content.decoded.data = &filter;
        item.requestedParameters.filter.content.decoded.type = &UA_TYPES[UA_TYPES_EVENTFILTER];
    }

    item.requestedParameters.queueSize = 1;
    item.requestedParameters.discardOldest = true;

    return UA_Client_MonitoredItems_createEvent(client, subscriptionId,
                                                UA_TIMESTAMPSTORETURN_BOTH, item,
                                                &monitoredItemId, handler, NULL);
}


/* Create event with empty filter */

START_TEST(generateEventEmptyFilter) {
        UA_NodeId eventNodeId;
        UA_StatusCode retval = eventSetup(&eventNodeId);
        ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);

        // add a monitored item
        UA_MonitoredItemCreateResult createResult = addMonitoredItem(handler_events_simple, false);
        ck_assert_uint_eq(createResult.statusCode, UA_STATUSCODE_BADEVENTFILTERINVALID);
} END_TEST


/* Ensure events are received with proper values */
START_TEST(generateEvents) {
    UA_NodeId eventNodeId;
    UA_StatusCode retval = eventSetup(&eventNodeId);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);

    // add a monitored item
    UA_MonitoredItemCreateResult createResult = addMonitoredItem(handler_events_simple, true);
    ck_assert_uint_eq(createResult.statusCode, UA_STATUSCODE_GOOD);
    monitoredItemId = createResult.monitoredItemId;
    // trigger the event
    retval = triggerEventLocked(eventNodeId, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER), NULL, UA_TRUE);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);

    // let the client fetch the event and check if the correct values were received
    notificationReceived = false;
    sleepUntilAnswer(publishingInterval + 100);
    retval = UA_Client_run_iterate(client, 0);
    sleepUntilAnswer(publishingInterval + 100);
    retval = UA_Client_run_iterate(client, 0);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(notificationReceived, true);
    ck_assert_uint_eq(createResult.revisedQueueSize, 1);

    // delete the monitoredItem
    UA_DeleteMonitoredItemsRequest deleteRequest;
    UA_DeleteMonitoredItemsRequest_init(&deleteRequest);
    deleteRequest.subscriptionId = subscriptionId;
    deleteRequest.monitoredItemIds = &monitoredItemId;
    deleteRequest.monitoredItemIdsSize = 1;

    UA_DeleteMonitoredItemsResponse deleteResponse =
        UA_Client_MonitoredItems_delete(client, deleteRequest);

    sleepUntilAnswer(publishingInterval + 100);
    ck_assert_uint_eq(deleteResponse.responseHeader.serviceResult, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(deleteResponse.resultsSize, 1);
    ck_assert_uint_eq(*(deleteResponse.results), UA_STATUSCODE_GOOD);

    UA_DeleteMonitoredItemsResponse_deleteMembers(&deleteResponse);
} END_TEST

static bool hasBaseModelChangeEventType(void) {

    UA_QualifiedName readBrowsename;
    UA_QualifiedName_init(&readBrowsename);
    UA_StatusCode retval = UA_Server_readBrowseName(server, UA_NODEID_NUMERIC(0, UA_NS0ID_BASEMODELCHANGEEVENTTYPE), &readBrowsename);
    UA_QualifiedName_deleteMembers(&readBrowsename);
    return !(retval == UA_STATUSCODE_BADNODEIDUNKNOWN);
}

START_TEST(createAbstractEvent) {
    if (!hasBaseModelChangeEventType())
        return;

    UA_NodeId eventNodeId = UA_NODEID_NULL;
    UA_NodeId abstractEventType = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEMODELCHANGEEVENTTYPE);
    serverMutexLock();
    UA_StatusCode retval = UA_Server_createEvent(server, abstractEventType, &eventNodeId);
    serverMutexUnlock();
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
} END_TEST

START_TEST(createAbstractEventWithParent) {
    if (!hasBaseModelChangeEventType())
        return;
    UA_NodeId eventNodeId = UA_NODEID_NULL;
    UA_NodeId abstractEventType = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEMODELCHANGEEVENTTYPE);
    serverMutexLock();
    // createEvent does not use a parent, so we are instead using addObjectNode
    UA_StatusCode retval = UA_Server_addObjectNode(server, UA_NODEID_NULL, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER),
                                                   UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
                                                   UA_QUALIFIEDNAME(0, "Abstract Event"), abstractEventType,
                                                   UA_ObjectAttributes_default, NULL, &eventNodeId);
    serverMutexUnlock();
    ck_assert_uint_eq(retval, UA_STATUSCODE_BADTYPEDEFINITIONINVALID);
} END_TEST

START_TEST(createNonAbstractEventWithParent) {
    UA_NodeId eventNodeId = UA_NODEID_NULL;
    serverMutexLock();
    // Our SimpleEventType is not abstract
    UA_StatusCode retval = UA_Server_addObjectNode(server, UA_NODEID_NULL, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER),
                                                   UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
                                                   UA_QUALIFIEDNAME(0, "Non-Abstract Event"), eventType,
                                                   UA_ObjectAttributes_default, NULL, &eventNodeId);
    serverMutexUnlock();
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
} END_TEST

static void
handler_events_propagate(UA_Client *lclient, UA_UInt32 subId, void *subContext,
                         UA_UInt32 monId, void *monContext,
                         size_t nEventFields, UA_Variant *eventFields) {
    UA_Boolean foundSeverity = UA_FALSE;
    UA_Boolean foundMessage = UA_FALSE;
    UA_Boolean foundType = UA_FALSE;
    UA_Boolean foundSource = UA_FALSE;
    ck_assert_uint_eq(*(UA_UInt32 *) monContext, monitoredItemId);
    ck_assert_uint_eq(nEventFields, nSelectClauses);
    // check all event fields
    for(size_t i = 0; i < nEventFields; i++) {
        // find out which attribute of the event is being looked at
        if(UA_Variant_hasScalarType(&eventFields[i], &UA_TYPES[UA_TYPES_UINT16])) {
            // Severity
            ck_assert_uint_eq(*((UA_UInt16 *) (eventFields[i].data)), 1000);
            foundSeverity = UA_TRUE;
        } else if(UA_Variant_hasScalarType(&eventFields[i], &UA_TYPES[UA_TYPES_LOCALIZEDTEXT])) {
            // Message
            UA_LocalizedText comp = UA_LOCALIZEDTEXT("en-US", "Generated Event");
            ck_assert(UA_String_equal(&((UA_LocalizedText *) eventFields[i].data)->locale, &comp.locale));
            ck_assert(UA_String_equal(&((UA_LocalizedText *) eventFields[i].data)->text, &comp.text));
            foundMessage = UA_TRUE;
        } else if(UA_Variant_hasScalarType(&eventFields[i], &UA_TYPES[UA_TYPES_NODEID])) {
            // either SourceNode or EventType
            UA_NodeId serverNameSpaceId = UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_VENDORSERVERINFO);
            if(UA_NodeId_equal((UA_NodeId *) eventFields[i].data, &eventType)) {
                // EventType
                foundType = UA_TRUE;
            } else if(UA_NodeId_equal((UA_NodeId *) eventFields[i].data, &serverNameSpaceId)) {
                // SourceNode
                foundSource = UA_TRUE;
            } else {
                ck_assert_msg(UA_FALSE, "NodeId doesn't match");
            }
        } else {
            ck_assert_msg(UA_FALSE, "Field doesn't match");
        }
    }
    ck_assert_uint_eq(foundMessage, UA_TRUE);
    ck_assert_uint_eq(foundSeverity, UA_TRUE);
    ck_assert_uint_eq(foundType, UA_TRUE);
    ck_assert_uint_eq(foundSource, UA_TRUE);
    notificationReceived = true;
}

START_TEST(uppropagation) {
    // trigger first event
    UA_NodeId eventNodeId = UA_NODEID_NULL;
    UA_StatusCode retval = eventSetup(&eventNodeId);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);

    //add a monitored item
    UA_MonitoredItemCreateResult createResult = addMonitoredItem(handler_events_propagate, true);
    ck_assert_uint_eq(createResult.statusCode, UA_STATUSCODE_GOOD);
    monitoredItemId = createResult.monitoredItemId;
    // trigger the event on a child of server, using namespaces in this case (no reason in particular)
    retval = triggerEventLocked(eventNodeId, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_VENDORSERVERINFO), NULL,
                                UA_TRUE);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);

    // let the client fetch the event and check if the correct values were received
    notificationReceived = false;
    sleepUntilAnswer(publishingInterval + 100);
    retval = UA_Client_run_iterate(client, 0);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(notificationReceived, true);
    ck_assert_uint_eq(createResult.revisedQueueSize, 1);

    // delete the monitoredItem
    UA_DeleteMonitoredItemsRequest deleteRequest;
    UA_DeleteMonitoredItemsRequest_init(&deleteRequest);
    deleteRequest.subscriptionId = subscriptionId;
    deleteRequest.monitoredItemIds = &monitoredItemId;
    deleteRequest.monitoredItemIdsSize = 1;

    UA_DeleteMonitoredItemsResponse deleteResponse =
        UA_Client_MonitoredItems_delete(client, deleteRequest);

    ck_assert_uint_eq(deleteResponse.responseHeader.serviceResult, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(deleteResponse.resultsSize, 1);
    ck_assert_uint_eq(*(deleteResponse.results), UA_STATUSCODE_GOOD);

    UA_DeleteMonitoredItemsResponse_deleteMembers(&deleteResponse);
} END_TEST

static void
handler_events_overflow(UA_Client *lclient, UA_UInt32 subId, void *subContext,
                        UA_UInt32 monId, void *monContext,
                        size_t nEventFields, UA_Variant *eventFields) {
    ck_assert_uint_eq(*(UA_UInt32 *) monContext, monitoredItemId);
    if(nEventFields == 1) {
        /* overflow was received */
        ck_assert(eventFields->type == &UA_TYPES[UA_TYPES_NODEID]);
        UA_NodeId comp = UA_NODEID_NUMERIC(0, UA_NS0ID_SIMPLEOVERFLOWEVENTTYPE);
        ck_assert((UA_NodeId_equal((UA_NodeId *) eventFields->data, &comp)));
        overflowNotificationReceived = UA_TRUE;
    } else if(nEventFields == 4) {
        /* other event was received */
        handler_events_simple(lclient, subId, subContext, monId,
                              monContext, nEventFields, eventFields);
    }
}

/* Ensures an eventQueueOverflowEvent is published when appropriate */
START_TEST(eventOverflow) {
    // add a monitored item
    UA_MonitoredItemCreateResult createResult = addMonitoredItem(handler_events_overflow, true);
    ck_assert_uint_eq(createResult.statusCode, UA_STATUSCODE_GOOD);
    monitoredItemId = createResult.monitoredItemId;

    // trigger first event
    UA_NodeId eventNodeId;
    UA_StatusCode retval = eventSetup(&eventNodeId);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    retval = triggerEventLocked(eventNodeId, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER), NULL, UA_FALSE);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    retval = triggerEventLocked(eventNodeId, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER), NULL, UA_TRUE);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);

    // fetch the events, ensure both the overflow and the original event are received
    notificationReceived = false;
    overflowNotificationReceived = true;
    sleepUntilAnswer(publishingInterval + 100);
    retval = UA_Client_run_iterate(client, 0);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(notificationReceived, true);
    ck_assert_uint_eq(overflowNotificationReceived, true);
    ck_assert_uint_eq(createResult.revisedQueueSize, 1);

    // delete the monitoredItem
    UA_DeleteMonitoredItemsRequest deleteRequest;
    UA_DeleteMonitoredItemsRequest_init(&deleteRequest);
    deleteRequest.subscriptionId = subscriptionId;
    deleteRequest.monitoredItemIds = &monitoredItemId;
    deleteRequest.monitoredItemIdsSize = 1;

    UA_DeleteMonitoredItemsResponse deleteResponse =
        UA_Client_MonitoredItems_delete(client, deleteRequest);

    ck_assert_uint_eq(deleteResponse.responseHeader.serviceResult, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(deleteResponse.resultsSize, 1);
    ck_assert_uint_eq(*(deleteResponse.results), UA_STATUSCODE_GOOD);

    UA_DeleteMonitoredItemsResponse_deleteMembers(&deleteResponse);
} END_TEST

START_TEST(multipleMonitoredItemsOneNode) {
    UA_UInt32 monitoredItemIdAr[3];

    /* set up monitored items */
    UA_MonitoredItemCreateRequest item;
    UA_MonitoredItemCreateRequest_init(&item);
    item.itemToMonitor.nodeId = UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER); // Root->Objects->Server
    item.itemToMonitor.attributeId = UA_ATTRIBUTEID_EVENTNOTIFIER;
    item.monitoringMode = UA_MONITORINGMODE_REPORTING;

    UA_EventFilter filter;
    UA_EventFilter_init(&filter);
    filter.selectClauses = selectClauses;
    filter.selectClausesSize = nSelectClauses;

    item.requestedParameters.filter.encoding = UA_EXTENSIONOBJECT_DECODED;
    item.requestedParameters.filter.content.decoded.data = &filter;
    item.requestedParameters.filter.content.decoded.type = &UA_TYPES[UA_TYPES_EVENTFILTER];
    item.requestedParameters.queueSize = 1;
    item.requestedParameters.discardOldest = true;

    for(size_t i = 0; i < 3; i++) {
        UA_MonitoredItemCreateResult result =
            UA_Client_MonitoredItems_createEvent(client, subscriptionId, UA_TIMESTAMPSTORETURN_BOTH,
                                                 item, NULL, handler_events_simple, NULL);
        ck_assert_uint_eq(result.statusCode, UA_STATUSCODE_GOOD);
        monitoredItemIdAr[i] = result.monitoredItemId;
    }

    // delete the three monitored items after another
    UA_DeleteMonitoredItemsRequest deleteRequest;
    UA_DeleteMonitoredItemsRequest_init(&deleteRequest);
    deleteRequest.subscriptionId = subscriptionId;
    deleteRequest.monitoredItemIdsSize = 1;
    UA_DeleteMonitoredItemsResponse deleteResponse;

    for(size_t i = 0; i < 3; i++) {
        deleteRequest.monitoredItemIds = &monitoredItemIdAr[i];
        deleteResponse = UA_Client_MonitoredItems_delete(client, deleteRequest);

        ck_assert_uint_eq(deleteResponse.responseHeader.serviceResult, UA_STATUSCODE_GOOD);
        ck_assert_uint_eq(deleteResponse.resultsSize, 1);
        ck_assert_uint_eq(*(deleteResponse.results), UA_STATUSCODE_GOOD);
        UA_DeleteMonitoredItemsResponse_deleteMembers(&deleteResponse);
    }
} END_TEST

START_TEST(eventStressing) {
    // add a monitored item
    UA_MonitoredItemCreateResult createResult = addMonitoredItem(handler_events_overflow, true);
    ck_assert_uint_eq(createResult.statusCode, UA_STATUSCODE_GOOD);
    monitoredItemId = createResult.monitoredItemId;

    // trigger a large amount of events, ensure the server doesnt crash because of it
    UA_NodeId eventNodeId;
    UA_StatusCode retval = eventSetup(&eventNodeId);
    ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    for(size_t i = 0; i < 20; i++) {
        for(size_t j = 0; j < 5; j++) {
            retval = triggerEventLocked(eventNodeId,
                                            UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER), NULL, UA_FALSE);
            ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
        }
        retval = UA_Client_run_iterate(client, 0);
        ck_assert_uint_eq(retval, UA_STATUSCODE_GOOD);
    }

    // delete the monitoredItem
    UA_DeleteMonitoredItemsRequest deleteRequest;
    UA_DeleteMonitoredItemsRequest_init(&deleteRequest);
    deleteRequest.subscriptionId = subscriptionId;
    deleteRequest.monitoredItemIds = &monitoredItemId;
    deleteRequest.monitoredItemIdsSize = 1;

    UA_DeleteMonitoredItemsResponse deleteResponse =
        UA_Client_MonitoredItems_delete(client, deleteRequest);

    ck_assert_uint_eq(deleteResponse.responseHeader.serviceResult, UA_STATUSCODE_GOOD);
    ck_assert_uint_eq(deleteResponse.resultsSize, 1);
    ck_assert_uint_eq(*(deleteResponse.results), UA_STATUSCODE_GOOD);

    UA_DeleteMonitoredItemsResponse_deleteMembers(&deleteResponse);
} END_TEST

#endif /* UA_ENABLE_SUBSCRIPTIONS_EVENTS */

/* Assumes subscriptions work fine with data change because of other unit test */
static Suite *testSuite_Client(void) {
    Suite *s = suite_create("Server Subscription Events");
    TCase *tc_server = tcase_create("Server Subscription Events");
#ifdef UA_ENABLE_SUBSCRIPTIONS_EVENTS
    tcase_add_unchecked_fixture(tc_server, setup, teardown);
    tcase_add_test(tc_server, generateEventEmptyFilter);
    tcase_add_test(tc_server, generateEvents);
    tcase_add_test(tc_server, createAbstractEvent);
    tcase_add_test(tc_server, createAbstractEventWithParent);
    tcase_add_test(tc_server, createNonAbstractEventWithParent);
    tcase_add_test(tc_server, uppropagation);
    tcase_add_test(tc_server, eventOverflow);
    tcase_add_test(tc_server, multipleMonitoredItemsOneNode);
    tcase_add_test(tc_server, eventStressing);
#endif /* UA_ENABLE_SUBSCRIPTIONS_EVENTS */
    suite_add_tcase(s, tc_server);

    return s;
}

int main(void) {
    Suite *s = testSuite_Client();
    SRunner *sr = srunner_create(s);
    srunner_set_fork_status(sr, CK_NOFORK);
    srunner_run_all(sr, CK_NORMAL);
    int number_failed = srunner_ntests_failed(sr);
    srunner_free(sr);
    return (number_failed == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
}