docs: prove that count endpoint works with distinct results

simulator-docs/src/main/asciidoc/rest-api.adoc

@@ -17,6 +17,7 @@ For each listed resource, the following operations are supported:
 * Listing all entries with a `GET` request to the root URI.
 ** Pagination and filtering are supported.
 * Counting all entries with a `GET /count` endpoint.
+** Note that the `?distinct=true` query parameter is required to count unique results.
 * Retrieving a single resource using the `GET /{id}` endpoint.
 
 All REST resources adhere to this pattern, with exceptions noted in subsequent sections.

simulator-samples/sample-rest/src/test/java/org/citrusframework/simulator/SimulatorRestIT.java

@@ -25,6 +25,7 @@
 import org.citrusframework.testng.spring.TestNGCitrusSpringSupport;
 import org.citrusframework.xml.XsdSchemaRepository;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.annotation.Bean;
@@ -49,10 +50,18 @@ public class SimulatorRestIT extends TestNGCitrusSpringSupport {
 
     private final String defaultResponse = "<DefaultResponse>This is a default response!</DefaultResponse>";
 
+    /**
+     * Test Http REST client configured to access the API
+     */
+    @Autowired
+    @Qualifier("apiClient")
+    private HttpClient apiClient;
+
     /**
      * Test Http REST client
      */
     @Autowired
+    @Qualifier("simulatorClient")
     private HttpClient simulatorClient;
 
     /**
@@ -263,6 +272,17 @@ public void testSimulationFailingExpectantly() {
         $(http().client(simulatorClient)
             .receive()
             .response(HttpStatus.OK));
+
+        // Make sure we receive exactly one record using "count" resources
+        $(http().client(apiClient)
+            .send()
+            .get("scenario-executions/count?headers=citrus_endpoint_uri~/services/rest/simulator/fail&scenarioName.contains=Fail&status.equals=2&distinct=true"));
+
+        $(http().client(apiClient)
+            .receive()
+            .response(HttpStatus.OK)
+            .getMessageBuilderSupport()
+            .body("1"));
     }
 
     /**
@@ -319,6 +339,13 @@ public HttpClient simulatorClient() {
                 .build();
         }
 
+        @Bean
+        public HttpClient apiClient() {
+            return CitrusEndpoints.http().client()
+                .requestUrl(String.format("http://localhost:%s/api", 8080))
+                .build();
+        }
+
         @Bean
         @ConditionalOnProperty(name = "simulator.mode", havingValue = "embedded")
         public BeforeSuite startEmbeddedSimulator() {

simulator-spring-boot/src/main/java/org/citrusframework/simulator/service/CriteriaQueryUtils.java

@@ -17,6 +17,7 @@
 package org.citrusframework.simulator.service;
 
 import static java.util.Objects.nonNull;
+import static org.springframework.data.domain.Pageable.unpaged;
 
 import jakarta.persistence.EntityManager;
 import jakarta.persistence.TypedQuery;
@@ -68,7 +69,10 @@ static <R> TypedQuery<Long> newSelectIdBySpecificationQuery(Class<R> entityClass
         criteriaQuery = orderByPageSort(page, root, criteriaBuilder, criteriaQuery);
 
         TypedQuery<Long> query = entityManager.createQuery(criteriaQuery);
-        query = selectPage(page, query);
+
+        if (!unpaged().equals(page)) {
+            query = selectPage(page, query);
+        }
 
         return query;
     }

simulator-spring-boot/src/main/java/org/citrusframework/simulator/service/ScenarioExecutionQueryService.java

@@ -275,7 +275,7 @@ private Specification<ScenarioExecution> buildMessageHeaderValueSpecification(Lo
 
     private static SetJoin<Message, MessageHeader> joinMessageHeaders(Root<ScenarioExecution> root) {
         return root.join(ScenarioExecution_.scenarioMessages, JoinType.LEFT)
-            .join(Message_.headers);
+            .join(Message_.headers, JoinType.LEFT);
     }
 
     private static Path<String> joinMessageHeadersAndGetValue(Root<ScenarioExecution> root) {

simulator-spring-boot/src/test/java/org/citrusframework/simulator/web/rest/ScenarioExecutionResourceIT.java

@@ -560,6 +560,7 @@ void getNonExistingScenarioExecution() throws Exception {
 
     @Nested
     class CorrectTimeOnScenarioExecution {
+
         public static final TemporalUnitLessThanOffset LESS_THAN_5_SECONDS = new TemporalUnitLessThanOffset(5, SECONDS);
 
         @Autowired