fix unpredictable results from GetPage method

ShoppingAssistantApi.Persistance/Repositories/MessagesRepository.cs

@@ -17,6 +17,21 @@ public class MessagesRepository : BaseRepository<Message>, IMessagesRepository
         pageSize = Math.Clamp(pageSize, 1, messageCount);
         var numberOfPages = messageCount / pageSize;
 
+        if (pageNumber > numberOfPages)
+        {
+            return new List<Message>();
+        }
+
+        if (pageNumber < 1)
+        {
+            throw new ArgumentOutOfRangeException();
+        }
+
+        if (pageSize < 1)
+        {
+            throw new ArgumentOutOfRangeException();
+        }
+
         return await _collection.Find(predicate)
                                 .Skip((numberOfPages - pageNumber) * pageSize)
                                 .Limit(pageSize)

ShoppingAssistantApi.Tests/Tests/WishlistsTests.cs

@@ -310,6 +310,8 @@ public class WishlistsTests : IClassFixture<TestingFactory<Program>>
         var responseString = await response.Content.ReadAsStringAsync();
         var document = JsonConvert.DeserializeObject<dynamic>(responseString);
 
+        Console.WriteLine(document);
+
         var personalWishlistsPageItems = Enumerable.ToList(document.data.personalWishlistsPage.items);
 
         Assert.Empty(personalWishlistsPageItems);
@@ -342,6 +344,9 @@ public class WishlistsTests : IClassFixture<TestingFactory<Program>>
         var responseString = await response.Content.ReadAsStringAsync();
         var document = JsonConvert.DeserializeObject<dynamic>(responseString);
 
+        Console.WriteLine(document);
+
+
         var personalWishlistsPageItems = Enumerable.ToList(document.data.personalWishlistsPage.items);
         var personalWishlistCreatedById = (string) personalWishlistsPageItems[0].createdById;
 
@@ -446,7 +451,17 @@ public class WishlistsTests : IClassFixture<TestingFactory<Program>>
         var content = new StringContent(jsonPayload, Encoding.UTF8, "application/json");
 
         using var response = await _httpClient.PostAsync("graphql", content);
-        Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
+        var responseString = await response.Content.ReadAsStringAsync();
+        var document = JsonConvert.DeserializeObject<dynamic>(responseString);
+
+        Console.WriteLine(document);
+
+
+        var messagesPageFromPersonalWishlistItems = Enumerable.ToList(document.data.messagesPageFromPersonalWishlist.items);
+
+        Assert.Empty(messagesPageFromPersonalWishlistItems);
     }
 
     [Fact]
@@ -476,6 +491,9 @@ public class WishlistsTests : IClassFixture<TestingFactory<Program>>
         var responseString = await response.Content.ReadAsStringAsync();
         var document = JsonConvert.DeserializeObject<dynamic>(responseString);
 
+        Console.WriteLine(document);
+
+
         var messagesPageFromPersonalWishlist = Enumerable.ToList(document.data.messagesPageFromPersonalWishlist.items);
         var firstMessageInPage = messagesPageFromPersonalWishlist[0];
         var secondMessageInPage = messagesPageFromPersonalWishlist[1];