further test for ListUsers with RestPagedAsync

Author: ChristopherLenz

FirebaseAdmin/FirebaseAdmin.Tests/Auth/FirebaseUserManagerTest.cs

@@ -15,8 +15,11 @@
 using System;
 using System.Collections.Generic;
 using System.Net;
+using System.Net.Http;
 using System.Threading.Tasks;
 using FirebaseAdmin.Tests;
+using Google.Api.Gax;
+using Google.Api.Gax.Rest;
 using Google.Apis.Auth.OAuth2;
 using Xunit;
 
@@ -118,6 +121,81 @@ await Assert.ThrowsAsync<FirebaseException>(
                 async () => await userManager.GetUserById("user1"));
         }
 
+        [Fact]
+        public async Task ListUsersPaged()
+        {
+            var nextPageToken = Guid.NewGuid().ToString();
+            var handlerInit = new MockMessageHandler()
+            {
+                Response = new DownloadAccountResponse()
+                {
+                    NextPageToken = nextPageToken,
+                    Users = new List<GetAccountInfoResponse.User>()
+                    {
+                        new GetAccountInfoResponse.User() { UserId = "user1" },
+                        new GetAccountInfoResponse.User() { UserId = "user2" },
+                        new GetAccountInfoResponse.User() { UserId = "user3" },
+                    },
+                },
+            };
+
+            var handlerSecondCall = new MockMessageHandler()
+            {
+                Response = new DownloadAccountResponse()
+                {
+                    NextPageToken = string.Empty,
+                    Users = new List<GetAccountInfoResponse.User>()
+                    {
+                        new GetAccountInfoResponse.User() { UserId = "user4" },
+                        new GetAccountInfoResponse.User() { UserId = "user5" },
+                        new GetAccountInfoResponse.User() { UserId = "user6" },
+                    },
+                },
+            };
+
+            var factory = new MockHttpClientFactory(new MultipleMockMessageHandler(new Dictionary<Func<HttpRequestMessage, bool>, MockMessageHandler>
+            {
+                { initMessage => initMessage.RequestUri.Query.Equals("?maxResults=3&nextPageToken="), handlerInit },
+                { initMessage => initMessage.RequestUri.Query.Equals($"?maxResults=3&nextPageToken={nextPageToken}"), handlerSecondCall },
+            }));
+
+            var userManager = new FirebaseUserManager(
+                new FirebaseUserManagerArgs
+                {
+                    Credential = MockCredential,
+                    ProjectId = MockProjectId,
+                    ClientFactory = factory,
+                });
+
+            var requestOptions = new ListUsersOptions();
+            var usersPage = new RestPagedAsyncEnumerable<ListUsersRequest, ExportedUserRecords, ExportedUserRecord>(
+                () => userManager.CreateListUserRequest(requestOptions),
+                new ListUsersPageManager());
+
+            var users = new List<ExportedUserRecord>();
+            var pageCounter = 0;
+
+            for (Page<ExportedUserRecord> userPage; (userPage = await usersPage.ReadPageAsync(3)) != null;)
+            {
+                pageCounter++;
+                users.AddRange(userPage);
+
+                if (string.IsNullOrEmpty(userPage.NextPageToken))
+                {
+                    break;
+                }
+            }
+
+            Assert.Equal(6, users.Count);
+            Assert.Equal(2, pageCounter);
+            Assert.Equal("user1", users[0].Uid);
+            Assert.Equal("user2", users[1].Uid);
+            Assert.Equal("user3", users[2].Uid);
+            Assert.Equal("user4", users[3].Uid);
+            Assert.Equal("user5", users[4].Uid);
+            Assert.Equal("user6", users[5].Uid);
+        }
+
         [Fact]
         public async Task ListUsers()
         {

FirebaseAdmin/FirebaseAdmin.Tests/MockMessageHandler.cs

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 using System;
+using System.Collections.Generic;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
@@ -53,7 +54,7 @@ public MockMessageHandler()
 
         public SetContentHeaders ApplyContentHeaders { get; set; }
 
-        protected override async Task<HttpResponseMessage> SendAsyncCore(
+        protected internal override async Task<HttpResponseMessage> SendAsyncCore(
             HttpRequestMessage request, CancellationToken cancellationToken)
         {
             if (request.Content != null)
@@ -116,15 +117,41 @@ public int Calls
             get { return this.calls; }
         }
 
+        protected internal abstract Task<HttpResponseMessage> SendAsyncCore(
+            HttpRequestMessage request, CancellationToken cancellationToken);
+
         protected sealed override Task<HttpResponseMessage> SendAsync(
           HttpRequestMessage request, CancellationToken cancellationToken)
         {
             Interlocked.Increment(ref this.calls);
             return this.SendAsyncCore(request, cancellationToken);
         }
+    }
 
-        protected abstract Task<HttpResponseMessage> SendAsyncCore(
-            HttpRequestMessage request, CancellationToken cancellationToken);
+    internal class MultipleMockMessageHandler : CountableMessageHandler
+    {
+        private readonly IDictionary<Func<HttpRequestMessage, bool>, MockMessageHandler> messageHandlers;
+
+        public MultipleMockMessageHandler(IDictionary<Func<HttpRequestMessage, bool>, MockMessageHandler> messageHandlers)
+        {
+            this.messageHandlers = messageHandlers;
+        }
+
+        protected internal override async Task<HttpResponseMessage> SendAsyncCore(
+            HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            foreach (var (requestCheck, mockMessageHandler) in this.messageHandlers)
+            {
+                // check if the messagehandler is responsible for the current request
+                if (requestCheck.Invoke(request))
+                {
+                    this.messageHandlers.Remove(requestCheck);
+                    return await mockMessageHandler.SendAsyncCore(request, cancellationToken);
+                }
+            }
+
+            return new HttpResponseMessage(HttpStatusCode.NotFound);
+        }
     }
 
     internal class MockHttpClientFactory : HttpClientFactory