bug/wiremock-1268 moving Scenario state change before global response delay (#1436)

Co-authored-by: Stef Heyenrath <Stef.Heyenrath@gmail.com>

examples/WireMock.Net.WebApplication.IIS/App.cs

@@ -1,29 +1,18 @@
 // Copyright © WireMock.Net
 
-using Microsoft.Extensions.Hosting;
-using System.Threading;
-using System.Threading.Tasks;
-
 namespace WireMock.Net.WebApplication;
 
-public class App : IHostedService
+public class App(IWireMockService service) : IHostedService
 {
-    private readonly IWireMockService _service;
-        
-    public App(IWireMockService service)
-    {
-        _service = service;
-    }
-
     public Task StartAsync(CancellationToken cancellationToken)
     {
-        _service.Start();
+        service.Start();
         return Task.CompletedTask;
     }
 
     public Task StopAsync(CancellationToken cancellationToken)
     {
-        _service.Stop();
+        service.Stop();
         return Task.CompletedTask;
     }
 }

examples/WireMock.Net.WebApplication.IIS/Program.cs

@@ -1,9 +1,5 @@
 // Copyright © WireMock.Net
 
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Logging;
 using WireMock.Settings;
 
 namespace WireMock.Net.WebApplication;

examples/WireMock.Net.WebApplication.IIS/WireMock.Net.WebApplication.IIS.csproj

@@ -15,7 +15,6 @@
     </ItemGroup>
 
     <ItemGroup>
-        <ProjectReference Include="..\..\src\WireMock.Net.Abstractions\WireMock.Net.Abstractions.csproj" />
         <ProjectReference Include="..\..\src\WireMock.Net\WireMock.Net.csproj" />
     </ItemGroup>
 

examples/WireMock.Net.WebApplication.IIS/WireMockService.cs

@@ -1,7 +1,5 @@
 // Copyright © WireMock.Net
 
-using System;
-using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Newtonsoft.Json;
 using WireMock.Admin.Requests;

examples/WireMock.Net.WebApplication.IIS/appsettings.json

@@ -15,7 +15,7 @@
     "WireMockServerSettings": {
         "StartAdminInterface": true,
         "Urls": [
-            "http://localhost"
+            "http://localhost:0"
         ]
     }
 }

examples/WireMock.Net.WebApplication.IIS/web.config

@@ -1,12 +1,17 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <configuration>
-  <!--
+    <!--
     Configure your application settings in appsettings.json. Learn more at http://go.microsoft.com/fwlink/?LinkId=786380
-  -->
+    -->
-  <system.webServer>
+    <system.webServer>
-    <handlers>
+        <handlers>
-      <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
+            <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
-    </handlers>
+        </handlers>
-    <aspNetCore processPath="%LAUNCHER_PATH%" arguments="%LAUNCHER_ARGS%" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" forwardWindowsAuthToken="false" />
+        <httpProtocol>
-  </system.webServer>
+            <customHeaders>
+                <add name="X-Frame-Options" value="SAMEORIGIN" />
+            </customHeaders>
+        </httpProtocol>
+        <aspNetCore processPath="%LAUNCHER_PATH%" arguments="%LAUNCHER_ARGS%" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" forwardWindowsAuthToken="false" />
+    </system.webServer>
 </configuration>

src/WireMock.Net.Minimal/Owin/WireMockMiddleware.cs

@@ -122,6 +122,14 @@ internal class WireMockMiddleware(
                 }
             }
 
+            // Transition scenario state immediately after matching, before any delay (global or
+            // per-mapping) so that concurrent retries arriving during a delay period see the
+            // updated state and match the correct next mapping instead of re-matching this one.
+            if (targetMapping.Scenario != null)
+            {
+                UpdateScenarioState(targetMapping);
+            }
+
             if (!targetMapping.IsAdminInterface && options.RequestProcessingDelay > TimeSpan.Zero)
             {
                 await Task.Delay(options.RequestProcessingDelay.Value).ConfigureAwait(false);
@@ -147,11 +155,6 @@ internal class WireMockMiddleware(
                 }
             }
 
-            if (targetMapping.Scenario != null)
-            {
-                UpdateScenarioState(targetMapping);
-            }
-
             if (!targetMapping.IsAdminInterface && targetMapping.Webhooks?.Length > 0)
             {
                 await SendToWebhooksAsync(targetMapping, request, response).ConfigureAwait(false);

test/WireMock.Net.Tests/StatefulBehaviorTests.cs

@@ -373,7 +373,7 @@ public class StatefulBehaviorTests
         // Act and Assert
         server.SetScenarioState(scenario, "Buy milk");
         server.Scenarios.First(s => s.Name == scenario).Should().BeEquivalentTo(new { Name = scenario, NextState = "Buy milk" });
-        
+
         var getResponse1 = await client.GetStringAsync("/todo/items", cancelationToken);
         getResponse1.Should().Be("Buy milk");
 
@@ -413,6 +413,120 @@ public class StatefulBehaviorTests
         action.Should().ThrowAsync<HttpRequestException>();
     }
 
+    [Fact]
+    public async Task Scenarios_FirstRequestWithDelay_StateTransitions_BeforeDelayCompletes()
+    {
+        // Arrange
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var path = $"/foo_{Guid.NewGuid()}";
+        using var server = WireMockServer.Start();
+
+        // Mapping 1: start state, has a 500 ms delay
+        server
+            .Given(Request.Create().WithPath(path).UsingGet())
+            .InScenario("1260")
+            .WillSetStateTo("State1")
+            .RespondWith(Response.Create()
+                .WithBody("delayed response")
+                .WithDelay(TimeSpan.FromMilliseconds(500)));
+
+        // Mapping 2: only matches after state has transitioned to "State1"
+        server
+            .Given(Request.Create().WithPath(path).UsingGet())
+            .InScenario("1260")
+            .WhenStateIs("State1")
+            .RespondWith(Response.Create().WithBody("immediate response"));
+
+        var client = new HttpClient();
+
+        // Act: fire request 1 but don't await it yet — it will sit in a 500 ms delay
+        var request1Task = client.GetStringAsync(server.Url + path, cancellationToken);
+
+        // Give the server a moment to match & transition state before the delay completes
+        await Task.Delay(100, cancellationToken);
+
+        // Request 2 is sent while request 1 is still being delayed.
+        // After the fix the state has already transitioned, so request 2 matches Mapping 2.
+        var response2 = await client.GetStringAsync(server.Url + path, cancellationToken);
+
+        var response1 = await request1Task;
+
+        // Assert
+        response1.Should().Be("delayed response");
+        response2.Should().Be("immediate response");
+    }
+
+    [Fact]
+    public async Task Scenarios_WithGlobalRequestProcessingDelay_StateTransitions_BeforeDelayCompletes()
+    {
+        // Arrange: use the global RequestProcessingDelay instead of a per-mapping delay
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var path = $"/foo_{Guid.NewGuid()}";
+        using var server = WireMockServer.Start();
+        server.AddGlobalProcessingDelay(TimeSpan.FromMilliseconds(500));
+
+        server
+            .Given(Request.Create().WithPath(path).UsingGet())
+            .InScenario("s")
+            .WillSetStateTo("State1")
+            .RespondWith(Response.Create().WithBody("delayed response"));
+
+        server
+            .Given(Request.Create().WithPath(path).UsingGet())
+            .InScenario("s")
+            .WhenStateIs("State1")
+            .RespondWith(Response.Create().WithBody("immediate response"));
+
+        var client = new HttpClient();
+
+        // Act
+        var request1Task = client.GetStringAsync(server.Url + path, cancellationToken);
+        await Task.Delay(100, cancellationToken);
+        var response2 = await client.GetStringAsync(server.Url + path, cancellationToken);
+        var response1 = await request1Task;
+
+        // Assert
+        response1.Should().Be("delayed response");
+        response2.Should().Be("immediate response");
+    }
+
+    [Fact]
+    public async Task Scenarios_WithDelay_And_TimesInSameState_Should_Transition_After_Required_Hits()
+    {
+        // Arrange
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var path = $"/foo_{Guid.NewGuid()}";
+        using var server = WireMockServer.Start();
+
+        // Mapping 1: requires 2 hits before transitioning; has a short delay
+        server
+            .Given(Request.Create().WithPath(path).UsingGet())
+            .InScenario("s")
+            .WillSetStateTo("State1", 2)
+            .RespondWith(Response.Create()
+                .WithBody("first")
+                .WithDelay(TimeSpan.FromMilliseconds(50)));
+
+        // Mapping 2: matches after state is "State1"
+        server
+            .Given(Request.Create().WithPath(path).UsingGet())
+            .InScenario("s")
+            .WhenStateIs("State1")
+            .RespondWith(Response.Create().WithBody("second"));
+
+        var client = new HttpClient();
+
+        // Act
+        var response1 = await client.GetStringAsync(server.Url + path, cancellationToken);
+        var response2 = await client.GetStringAsync(server.Url + path, cancellationToken);
+        var response3 = await client.GetStringAsync(server.Url + path, cancellationToken);
+
+        // Assert: state only transitions after 2 hits, so request 3 is the first to match Mapping 2
+        response1.Should().Be("first");
+        response2.Should().Be("first");
+        response3.Should().Be("second");
+    }
+
     [Fact]
     public async Task Scenarios_Should_process_request_if_equals_state_and_multiple_state_defined()
     {