fix(entity): calculate the count of entities when offset is out of range (#851)

Author: bobeal

search-service/src/main/kotlin/com/egm/stellio/search/service/QueryService.kt

@@ -38,14 +38,15 @@ class QueryService(
                 queryParams,
                 accessRightFilter
             )
-            if (entitiesIds.isEmpty())
-                return@either Pair<List<JsonLdEntity>, Int>(emptyList(), 0)
-
             val count = temporalEntityAttributeService.getCountForEntities(
                 queryParams,
                 accessRightFilter
             ).bind()
 
+            // we can have an empty list of entities with a non-zero count (e.g., offset too high)
+            if (entitiesIds.isEmpty())
+                return@either Pair<List<JsonLdEntity>, Int>(emptyList(), count)
+
             val entitiesPayloads =
                 entityPayloadService.retrieve(entitiesIds)
                     .map { toJsonLdEntity(it, listOf(queryParams.context)) }

search-service/src/test/kotlin/com/egm/stellio/search/service/QueryServiceTests.kt

@@ -97,14 +97,13 @@ class QueryServiceTests {
     @Test
     fun `it should return an empty list if no entity matched the query`() = runTest {
         coEvery { temporalEntityAttributeService.getForEntities(any(), any()) } returns emptyList()
+        coEvery { temporalEntityAttributeService.getCountForEntities(any(), any()) } returns 0.right()
 
         queryService.queryEntities(buildDefaultQueryParams()) { null }
             .shouldSucceedWith {
                 assertEquals(0, it.second)
                 assertTrue(it.first.isEmpty())
             }
-
-        coVerify { temporalEntityAttributeService.getCountForEntities(any(), any()) wasNot Called }
     }
 
     @Test