Fix max redirect count (#20428)

Without this change, RedirectHandler always follows MaxRedirects + 1. If MaxRedirects was initially set to 1, the body of the while statement is executed twice. This defect expresses itself when calling WebApplicationFactory<Startup>.CreateClient() with WebApplicationFactoryClientOptions.MaxAutomaticRedirections >= 1 and .AllowAutoRedirects = true in integration tests.

Author: NetworkAndSoftware

src/Mvc/Mvc.Testing/src/Handlers/RedirectHandler.cs

@@ -54,7 +54,7 @@ protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage
             var originalRequestContent = HasBody(request) ? await DuplicateRequestContent(request) : null;
             CopyRequestHeaders(request.Headers, redirectRequest.Headers);
             var response = await base.SendAsync(request, cancellationToken);
-            while (IsRedirect(response) && remainingRedirects >= 0)
+            while (IsRedirect(response) && remainingRedirects > 0)
             {
                 remainingRedirects--;
                 UpdateRedirectRequest(response, redirectRequest, originalRequestContent);
@@ -168,4 +168,4 @@ private bool IsRedirect(HttpResponseMessage response) =>
                 response.StatusCode == HttpStatusCode.RedirectKeepVerb ||
                 (int)response.StatusCode == 308;
     }
-}
+}