Fix Collection was modified exception in test

test/Microsoft.AspNetCore.Session.Tests/SessionTests.cs

@@ -259,6 +259,7 @@ namespace Microsoft.AspNetCore.Session
                 var client = server.CreateClient();
                 var response = await client.GetAsync(string.Empty);
                 response.EnsureSuccessStatusCode();
+            }
 
             var sessionLogMessages = sink.Writes.OnlyMessagesFromSource<DistributedSession>().ToArray();
 
@@ -268,7 +269,6 @@ namespace Microsoft.AspNetCore.Session
             Assert.Contains("stored", sessionLogMessages[1].State.ToString());
             Assert.Equal(LogLevel.Debug, sessionLogMessages[1].LogLevel);
         }
-        }
 
         [Fact]
         public async Task ExpiredSession_LogsWarning()
@@ -303,6 +303,7 @@ namespace Microsoft.AspNetCore.Session
                     services.AddSession(o => o.IdleTimeout = TimeSpan.FromMilliseconds(30));
                 });
 
+            string result;
             using (var server = new TestServer(builder))
             {
                 var client = server.CreateClient();
@@ -313,10 +314,12 @@ namespace Microsoft.AspNetCore.Session
                 var cookie = SetCookieHeaderValue.ParseList(response.Headers.GetValues("Set-Cookie").ToList()).First();
                 client.DefaultRequestHeaders.Add("Cookie", new CookieHeaderValue(cookie.Name, cookie.Value).ToString());
                 Thread.Sleep(50);
-                Assert.Equal("2", await client.GetStringAsync("/second"));
+                result = await client.GetStringAsync("/second");
+            }
 
             var sessionLogMessages = sink.Writes.OnlyMessagesFromSource<DistributedSession>().ToArray();
 
+            Assert.Equal("2", result);
             Assert.Equal(3, sessionLogMessages.Length);
             Assert.Contains("started", sessionLogMessages[0].State.ToString());
             Assert.Contains("stored", sessionLogMessages[1].State.ToString());
@@ -325,7 +328,6 @@ namespace Microsoft.AspNetCore.Session
             Assert.Equal(LogLevel.Debug, sessionLogMessages[1].LogLevel);
             Assert.Equal(LogLevel.Warning, sessionLogMessages[2].LogLevel);
         }
-        }
 
         [Fact]
         public async Task RefreshesSession_WhenSessionData_IsNotModified()
@@ -527,6 +529,7 @@ namespace Microsoft.AspNetCore.Session
                 var client = server.CreateClient();
                 var response = await client.GetAsync(string.Empty);
                 response.EnsureSuccessStatusCode();
+            }
 
             var sessionLogMessages = sink.Writes.OnlyMessagesFromSource<DistributedSession>().ToArray();
 
@@ -534,7 +537,6 @@ namespace Microsoft.AspNetCore.Session
             Assert.Contains("Session cache read exception", sessionLogMessages[0].State.ToString());
             Assert.Equal(LogLevel.Error, sessionLogMessages[0].LogLevel);
         }
-        }
 
         [Fact]
         public async Task SessionLogsCacheWriteException()
@@ -566,6 +568,7 @@ namespace Microsoft.AspNetCore.Session
                 var client = server.CreateClient();
                 var response = await client.GetAsync(string.Empty);
                 response.EnsureSuccessStatusCode();
+            }
 
             var sessionLogMessages = sink.Writes.OnlyMessagesFromSource<DistributedSession>().ToArray();
 
@@ -578,7 +581,6 @@ namespace Microsoft.AspNetCore.Session
             Assert.Contains("Error closing the session.", sessionMiddlewareLogMessages[0].State.ToString());
             Assert.Equal(LogLevel.Error, sessionMiddlewareLogMessages[0].LogLevel);
         }
-        }
 
         [Fact]
         public async Task SessionLogsCacheRefreshException()
@@ -610,6 +612,7 @@ namespace Microsoft.AspNetCore.Session
                 var client = server.CreateClient();
                 var response = await client.GetAsync(string.Empty);
                 response.EnsureSuccessStatusCode();
+            }
 
             var sessionLogMessages = sink.Writes.OnlyMessagesFromSource<SessionMiddleware>().ToArray();
 
@@ -617,7 +620,6 @@ namespace Microsoft.AspNetCore.Session
             Assert.Contains("Error closing the session.", sessionLogMessages[0].State.ToString());
             Assert.Equal(LogLevel.Error, sessionLogMessages[0].LogLevel);
         }
-        }
 
         private class TestClock : ISystemClock
         {