Add an optional experimental feature that allows the VS extension to let the the discovered bindings written out to a file.

Reqnroll/Bindings/Discovery/RuntimeBindingRegistryBuilder.cs

@@ -1,11 +1,12 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reflection;
+using Reqnroll.Bindings.Provider;
 using Reqnroll.Bindings.Reflection;
 using Reqnroll.Configuration;
 using Reqnroll.Infrastructure;
 using Reqnroll.PlatformCompatibility;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
 
 namespace Reqnroll.Bindings.Discovery
 {
@@ -15,13 +16,15 @@ public class RuntimeBindingRegistryBuilder : IRuntimeBindingRegistryBuilder
         private readonly IReqnrollAttributesFilter _reqnrollAttributesFilter;
         private readonly IBindingAssemblyLoader _bindingAssemblyLoader;
         private readonly ReqnrollConfiguration _reqnrollConfiguration;
+        private readonly IBindingProviderService _bindingProviderService;
 
-        public RuntimeBindingRegistryBuilder(IRuntimeBindingSourceProcessor bindingSourceProcessor, IReqnrollAttributesFilter reqnrollAttributesFilter, IBindingAssemblyLoader bindingAssemblyLoader, ReqnrollConfiguration reqnrollConfiguration)
+        public RuntimeBindingRegistryBuilder(IRuntimeBindingSourceProcessor bindingSourceProcessor, IReqnrollAttributesFilter reqnrollAttributesFilter, IBindingAssemblyLoader bindingAssemblyLoader, ReqnrollConfiguration reqnrollConfiguration, IBindingProviderService bindingProviderService)
         {
             _bindingSourceProcessor = bindingSourceProcessor;
             _reqnrollAttributesFilter = reqnrollAttributesFilter;
             _bindingAssemblyLoader = bindingAssemblyLoader;
             _reqnrollConfiguration = reqnrollConfiguration;
+            _bindingProviderService = bindingProviderService;
         }
 
         public Assembly[] GetBindingAssemblies(Assembly testAssembly)
@@ -63,6 +66,7 @@ protected virtual Type[] GetAssemblyTypes(Assembly assembly, out string[] typeLo
         public void BuildingCompleted()
         {
             _bindingSourceProcessor.BuildingCompleted();
+            _bindingProviderService.OnBindingRegistryBuildingCompleted();
         }
 
         //internal - for testing

Reqnroll/Bindings/Provider/BindingJsonSourceGenerator.cs

@@ -4,8 +4,10 @@
 namespace Reqnroll.Bindings.Provider;
 
 [JsonSourceGenerationOptions(
-    PropertyNamingPolicy = JsonKnownNamingPolicy.Unspecified, // We specifiy the names explicitly
-    UseStringEnumConverter = true)] // use strings instead of numbers for enums
+    PropertyNamingPolicy = JsonKnownNamingPolicy.Unspecified, // We specify the names explicitly
+    UseStringEnumConverter = true, // use strings instead of numbers for enums
+    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull // Ignore null properties
+    )] 
 [JsonSerializable(typeof(BindingData))]
 internal partial class BindingJsonSourceGenerator : JsonSerializerContext
 {

Reqnroll/Bindings/Provider/BindingProviderService.cs

@@ -2,24 +2,76 @@
 using Reqnroll.Bindings.Provider.Data;
 using Reqnroll.Bindings.Reflection;
 using Reqnroll.BoDi;
+using Reqnroll.CommonModels;
 using Reqnroll.Configuration;
+using Reqnroll.EnvironmentAccess;
 using Reqnroll.Formatters.Configuration;
 using Reqnroll.Infrastructure;
+using System;
+using System.Diagnostics;
+using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Text;
 using System.Text.Json;
 
 namespace Reqnroll.Bindings.Provider;
 
-public class BindingProviderService
+public interface IBindingProviderService
 {
+    void OnBindingRegistryBuildingCompleted();
+}
+
+public class BindingProviderService(IBindingRegistry bindingRegistry, ITestAssemblyProvider testAssemblyProvider, IEnvironmentWrapper environmentWrapper) : IBindingProviderService
+{
+    /// <summary>
+    /// Invoked by the Visual Studio extension connectors. Do not remove or change the signature.
+    /// </summary>
     public static string DiscoverBindings(Assembly testAssembly, string jsonConfiguration)
     {
         if (string.IsNullOrWhiteSpace(jsonConfiguration)) jsonConfiguration = "{}";
         var globalContainer = CreateGlobalContainer(testAssembly, jsonConfiguration);
         var bindingRegistryBuilder = globalContainer.Resolve<IRuntimeBindingRegistryBuilder>();
         BuildBindingRegistry(testAssembly, bindingRegistryBuilder);
         var bindingRegistry = globalContainer.Resolve<IBindingRegistry>();
+        return GetDiscoveredBindingsFromRegistry(bindingRegistry, testAssembly);
+    }
+
+    private const string REQNROLL_BINDING_OUTPUT_ENVIRONMENT_VARIABLE = "REQNROLL_BINDING_OUTPUT";
+
+    public void OnBindingRegistryBuildingCompleted()
+    {
+        // Experimental feature: This code allows the Visual Studio extension to instruct saving the discovered bindings to a file
+        // using an environment variable during the test run.
+        // This might be used as an alternative to invoking the `DiscoverBindings` method, because that needs the test assembly to be
+        // fully loaded and this is sometimes problematic.
+
+        if (environmentWrapper.GetEnvironmentVariable(REQNROLL_BINDING_OUTPUT_ENVIRONMENT_VARIABLE) is ISuccess<string> environmentVariable &&
+            !string.IsNullOrWhiteSpace(environmentVariable.Result))
+        {
+            var outputFilePath = environmentVariable.Result.Equals("true", StringComparison.OrdinalIgnoreCase) ? "reqnroll_bindings.json" :
+                environmentVariable.Result.Trim();
+
+            outputFilePath = Path.GetFullPath(outputFilePath);
+            TrySaveBindings(outputFilePath);
+        }
+    }
+
+    private void TrySaveBindings(string outputFilePath)
+    {
+        try
+        {
+            var bindingsJson = GetDiscoveredBindingsFromRegistry(bindingRegistry, testAssemblyProvider.TestAssembly);
+            File.WriteAllText(outputFilePath, bindingsJson, Encoding.UTF8);
+        }
+        catch (Exception ex)
+        {
+            Debug.WriteLine(ex, "Writing bindings failed.");
+        }
+    }
+
+    private static string GetDiscoveredBindingsFromRegistry(IBindingRegistry bindingRegistry, Assembly testAssembly)
+    {
         var resultData = ParseDiscoveryResult(bindingRegistry, testAssembly);
         var jsonString = JsonSerializer.Serialize(resultData, BindingJsonSourceGenerator.Default.BindingData);
         return jsonString;
@@ -145,5 +197,4 @@ private static IObjectContainer CreateGlobalContainer(Assembly testAssembly, str
         var configurationProvider = new JsonStringRuntimeConfigurationProvider(jsonConfiguration);
         return containerBuilder.CreateGlobalContainer(testAssembly, configurationProvider);
     }
-
 }

Reqnroll/Infrastructure/DefaultDependencyProvider.cs

@@ -1,11 +1,11 @@
-using System;
 using Gherkin.CucumberMessages;
 using Reqnroll.Analytics;
 using Reqnroll.Analytics.AppInsights;
 using Reqnroll.Analytics.UserId;
 using Reqnroll.Bindings;
 using Reqnroll.Bindings.CucumberExpressions;
 using Reqnroll.Bindings.Discovery;
+using Reqnroll.Bindings.Provider;
 using Reqnroll.BindingSkeletons;
 using Reqnroll.BoDi;
 using Reqnroll.Configuration;
@@ -27,6 +27,7 @@
 using Reqnroll.Time;
 using Reqnroll.Tracing;
 using Reqnroll.Utils;
+using System;
 
 namespace Reqnroll.Infrastructure
 {
@@ -62,6 +63,7 @@ public virtual void RegisterGlobalContainerDefaults(ObjectContainer container)
             container.RegisterTypeAs<BindingInvoker, IAsyncBindingInvoker>();
             container.RegisterTypeAs<BindingDelegateInvoker, IBindingDelegateInvoker>();
             container.RegisterTypeAs<TestObjectResolver, ITestObjectResolver>();
+            container.RegisterTypeAs<BindingProviderService, IBindingProviderService>();
 
             container.RegisterTypeAs<StepDefinitionSkeletonProvider, IStepDefinitionSkeletonProvider>();
             container.RegisterTypeAs<DefaultSkeletonTemplateProvider, ISkeletonTemplateProvider>();

Tests/Reqnroll.RuntimeTests/RuntimeBindingRegistryBuilderTests.cs

@@ -5,6 +5,7 @@
 using Xunit;
 using Reqnroll.Bindings;
 using Reqnroll.Bindings.Discovery;
+using Reqnroll.Bindings.Provider;
 using Reqnroll.Configuration;
 using Reqnroll.Infrastructure;
 
@@ -226,7 +227,7 @@ public void GivenAndWhen()
 
         private RuntimeBindingRegistryBuilder CreateSut()
         {
-            return new RuntimeBindingRegistryBuilder(bindingSourceProcessorStub, new ReqnrollAttributesFilter(), new Mock<IBindingAssemblyLoader>().Object, ConfigurationLoader.GetDefault());
+            return new RuntimeBindingRegistryBuilder(bindingSourceProcessorStub, new ReqnrollAttributesFilter(), new Mock<IBindingAssemblyLoader>().Object, ConfigurationLoader.GetDefault(), new Mock<IBindingProviderService>().Object);
         }
 
         [Fact]