Automatically register SpecFlow bindings (#25)

* Search for BindingAttribute inside lib
* add AutoRegisterBindings

Contributor: @304NotModified
+semver: feature

Author: 304NotModified

README.md

@@ -23,13 +23,6 @@ PM> Install-Package SolidToken.SpecFlow.DependencyInjection
 
 Create a static method somewhere in the SpecFlow project (recommended to put it into the ```Support``` folder) that returns an Microsoft.Extensions.DependencyInjection ```IServiceCollection``` and tag it with the `[ScenarioDependencies]` attribute. Configure your dependencies for the scenario execution within the method. You also have to register the step definition classes, that you can do by either registering all classes marked with the ```[Binding]``` attribute:
 
-```csharp
-foreach (var type in typeof(TestDependencies).Assembly.GetTypes().Where(t => Attribute.IsDefined(t, typeof(BindingAttribute))))
-{
-    services.AddSingleton(type);
-}
-```
-
 A typical dependency builder method probably looks like this:
 
 ```csharp
@@ -38,13 +31,6 @@ public static IServiceCollection CreateServices()
 {
     var services = new ServiceCollection();
 
-    // TODO: add customizations, stubs required for testing
-
-    foreach (var type in typeof(TestDependencies).Assembly.GetTypes().Where(t => Attribute.IsDefined(t, typeof(BindingAttribute))))
-    {
-        services.AddSingleton(type);
-    }
-
     return services;
 }
 ```

SpecFlow.DependencyInjection.Tests/TestDependencies.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Linq;
 using Microsoft.Extensions.DependencyInjection;
-using TechTalk.SpecFlow;
 
 namespace SolidToken.SpecFlow.DependencyInjection.Tests
 {
@@ -18,14 +17,6 @@ public static IServiceCollection CreateServices()
             // ContextInjectionScope (by using AddScoped instead of AddTransient, the context will be scoped to the Feature across bindings)
             services.AddScoped<TestContext>();
 
-            // NOTE: This line is essential so that Microsoft.Extensions.DependencyInjection knows
-            // about the SpecFlow bindings (something normally BoDi does automatically).
-            // TODO: Find out if we can make this part of the Plugin
-            foreach (var type in typeof(TestDependencies).Assembly.GetTypes().Where(t => Attribute.IsDefined(t, typeof(BindingAttribute))))
-            {
-                services.AddSingleton(type);
-            }
-
             return services;
         }
     }

SpecFlow.DependencyInjection/ScenarioDependenciesAttribute.cs

@@ -5,5 +5,9 @@ namespace SolidToken.SpecFlow.DependencyInjection
     [AttributeUsage(AttributeTargets.Method)]
     public class ScenarioDependenciesAttribute : Attribute
     {
+        /// <summary>
+        /// Automatically register all SpecFlow bindings
+        /// </summary>
+        public bool AutoRegisterBindings { get; set; } = true;
     }
 }

SpecFlow.DependencyInjection/ServiceCollectionFinder.cs

@@ -2,6 +2,7 @@
 using System.Linq;
 using System.Reflection;
 using Microsoft.Extensions.DependencyInjection;
+using TechTalk.SpecFlow;
 using TechTalk.SpecFlow.Bindings;
 
 namespace SolidToken.SpecFlow.DependencyInjection
@@ -34,15 +35,39 @@ protected virtual Func<IServiceCollection> FindCreateScenarioServiceCollection()
             {
                 foreach (var type in assembly.GetTypes())
                 {
-                    foreach (var methodInfo in type
-                        .GetMethods(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public)
-                        .Where(m => Attribute.IsDefined((MemberInfo)m, typeof(ScenarioDependenciesAttribute))))
+                    foreach (var methodInfo in type.GetMethods(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
                     {
-                        return () => (IServiceCollection)methodInfo.Invoke(null, null);
+                        var scenarioDependenciesAttribute = (ScenarioDependenciesAttribute)Attribute.GetCustomAttribute(methodInfo, typeof(ScenarioDependenciesAttribute));
+
+                        if (scenarioDependenciesAttribute != null)
+                        {
+                            return () =>
+                            {
+                                var serviceCollection = GetServiceCollection(methodInfo);
+                                if (scenarioDependenciesAttribute.AutoRegisterBindings)
+                                {
+                                    AddBindingAttributes(assembly, serviceCollection);
+                                }
+                                return serviceCollection;
+                            };
+                        }
                     }
                 }
             }
             return null;
         }
+
+        private static IServiceCollection GetServiceCollection(MethodBase methodInfo)
+        {
+            return (IServiceCollection)methodInfo.Invoke(null, null);
+        }
+
+        private static void AddBindingAttributes(Assembly assembly, IServiceCollection serviceCollection)
+        {
+            foreach (var type in assembly.GetTypes().Where(t => Attribute.IsDefined(t, typeof(BindingAttribute))))
+            {
+                serviceCollection.AddSingleton(type);
+            }
+        }
     }
 }