Improved message when [ScenarioDependencies] can't be found or has an incorrect return type (Reqnroll.Microsoft.Extensions.DependencyInjection)

CHANGELOG.md

@@ -1,6 +1,7 @@
 # [vNext]
 
 ## Improvements:
+* Microsoft.Extensions.DependencyInjection.ReqnrollPlugin: Improved message when [ScenarioDependencies] can't be found or has an incorrect return type (#494)
 
 ## Bug fixes:
 * Fix: Microsoft.Extensions.DependencyInjection.ReqnrollPlugin, the plugin was only searching for [ScenarioDependencies] in assemblies with step definitions (#477)

Plugins/Reqnroll.Microsoft.Extensions.DependencyInjection.ReqnrollPlugin/InvalidScenarioDependenciesException.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Reqnroll.Microsoft.Extensions.DependencyInjection;
+
+[Serializable]
+public class InvalidScenarioDependenciesException(string reason) : ReqnrollException("[ScenarioDependencies] should return IServiceCollection but " + reason)
+{
+    public override string HelpLink { get; set; } = "https://go.reqnroll.net/doc-msdi";
+}

Plugins/Reqnroll.Microsoft.Extensions.DependencyInjection.ReqnrollPlugin/MissingScenarioDependenciesException.cs

@@ -1,14 +1,32 @@
 using System;
+using System.Collections.Generic;
 
 namespace Reqnroll.Microsoft.Extensions.DependencyInjection
 {
     [Serializable]
     public class MissingScenarioDependenciesException : ReqnrollException
     {
         public MissingScenarioDependenciesException()
-            : base("No method marked with [ScenarioDependencies] attribute found.")
+            : this([])
         {
-            HelpLink = "https://go.reqnroll.net/doc-msdi";
         }
+
+        public MissingScenarioDependenciesException(IList<string> assemblyNames)
+            : base(CreateMessage(assemblyNames))
+        {
+
+        }
+
+        private static string CreateMessage(IList<string> assemblyNames)
+        {
+            var message = "No method marked with [ScenarioDependencies] attribute found. It should be a (public or non-public) static method.";
+            if (assemblyNames.Count > 0)
+            {
+                message += $" Scanned assemblies: {string.Join(", ", assemblyNames)}.";
+            }
+            return message;
+        }
+
+        public override string HelpLink { get; set; } = "https://go.reqnroll.net/doc-msdi";
     }
 }

Plugins/Reqnroll.Microsoft.Extensions.DependencyInjection.ReqnrollPlugin/ServiceCollectionFinder.cs

@@ -28,7 +28,7 @@ public ServiceCollectionFinder(ITestRunnerManager testRunnerManager)
             {
                 foreach (var type in assembly.GetTypes())
                 {
-                    foreach (var methodInfo in type.GetMethods(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
+                    foreach (MethodInfo methodInfo in type.GetMethods(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
                     {
                         var scenarioDependenciesAttribute = (ScenarioDependenciesAttribute)Attribute.GetCustomAttribute(methodInfo, typeof(ScenarioDependenciesAttribute));
 
@@ -44,12 +44,28 @@ public ServiceCollectionFinder(ITestRunnerManager testRunnerManager)
                     }
                 }
             }
-            throw new MissingScenarioDependenciesException();
+            var assemblyNames = assemblies.Select(a => a.GetName().Name).ToList();
+            throw new MissingScenarioDependenciesException(assemblyNames);
         }
 
-        private static IServiceCollection GetServiceCollection(MethodBase methodInfo)
+        private static IServiceCollection GetServiceCollection(MethodInfo methodInfo)
         {
-            return (IServiceCollection)methodInfo.Invoke(null, null);
+            var serviceCollection = methodInfo.Invoke(null, null);
+            if(methodInfo.ReturnType == typeof(void))
+            {
+                throw new InvalidScenarioDependenciesException("the method doesn't return a value.");
+            }
+
+            if (serviceCollection == null)
+            {
+                throw new InvalidScenarioDependenciesException("returned null.");
+            }
+
+            if (serviceCollection is not IServiceCollection collection)
+            {
+                throw new InvalidScenarioDependenciesException($"returned {serviceCollection.GetType()}.");
+            }
+            return collection;
         }
 
         private static void AddBindingAttributes(IEnumerable<Assembly> bindingAssemblies, IServiceCollection serviceCollection)

Tests/Reqnroll.PluginTests/Microsoft.Extensions.DependencyInjection/ServiceCollectionFinderTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using FluentAssertions;
@@ -27,7 +28,68 @@ public void GetServiceCollection_HappyPath_ResolvesCorrectServiceCollection()
         var testService = serviceProvider.GetRequiredService<ITestInterface>();
         testService.Name.Should().Be("ValidStartWithAutoRegister");
     }
-
+
+    [Fact]
+    public void GetServiceCollection_MethodIsVoid_ThrowsInvalidScenarioDependenciesException()
+    {
+        // Arrange
+        var testRunnerManagerMock = CreateTestRunnerManagerMock(typeof(InvalidStartVoid));
+        var sut = new ServiceCollectionFinder(testRunnerManagerMock.Object);
+
+        // Act
+        var act = () => sut.GetServiceCollection();
+
+        // Assert
+        act.Should().Throw<InvalidScenarioDependenciesException>()
+           .WithMessage("[ScenarioDependencies] should return IServiceCollection but the method doesn't return a value.");
+    }
+
+    [Fact]
+    public void GetServiceCollection_MethodReturnsNull_ThrowsInvalidScenarioDependenciesException()
+    {
+        // Arrange
+        var testRunnerManagerMock = CreateTestRunnerManagerMock(typeof(InvalidStartNull));
+        var sut = new ServiceCollectionFinder(testRunnerManagerMock.Object);
+
+        // Act
+        var act = () => sut.GetServiceCollection();
+
+        // Assert
+        act.Should().Throw<InvalidScenarioDependenciesException>()
+           .WithMessage("[ScenarioDependencies] should return IServiceCollection but returned null.");
+    }
+
+
+    [Fact]
+    public void GetServiceCollection_MethodReturnsInvalidType_ThrowsInvalidScenarioDependenciesException()
+    {
+        // Arrange
+        var testRunnerManagerMock = CreateTestRunnerManagerMock(typeof(InvalidStartWrongType));
+        var sut = new ServiceCollectionFinder(testRunnerManagerMock.Object);
+
+        // Act
+        var act = () => sut.GetServiceCollection();
+
+        // Assert
+        act.Should().Throw<InvalidScenarioDependenciesException>()
+           .WithMessage("[ScenarioDependencies] should return IServiceCollection but returned System.Collections.Generic.List`1[System.String].");
+    }
+
+    [Fact]
+    public void GetServiceCollection_NotFound_ThrowsMissingScenarioDependenciesException()
+    {
+        // Arrange
+        var testRunnerManagerMock = CreateTestRunnerManagerMock(typeof(ServiceCollectionFinderTests));
+        var sut = new ServiceCollectionFinder(testRunnerManagerMock.Object);
+
+        // Act
+        var act = () => sut.GetServiceCollection();
+
+        // Assert
+        act.Should().Throw<MissingScenarioDependenciesException>()
+           .WithMessage("No method marked with [ScenarioDependencies] attribute found. It should be a (public or non-public) static method. Scanned assemblies: Reqnroll.PluginTests.");
+    }
+
     [Fact]
     public void GetServiceCollection_AutoRegisterBindingsTrue_RegisterBindingsAsScoped()
     {
@@ -62,6 +124,11 @@ private static Mock<ITestRunnerManager> CreateTestRunnerManagerMock(params Type[
     {
         var assemblyMock = new Mock<Assembly>();
         assemblyMock.Setup(m => m.GetTypes()).Returns(types.ToArray());
+        if (types.Length > 0)
+        {
+            var assembly = types[0].Assembly;
+            assemblyMock.Setup(m => m.GetName()).Returns(assembly.GetName());
+        }
 
         var testRunnerManagerMock = new Mock<ITestRunnerManager>();
         testRunnerManagerMock.Setup(m => m.BindingAssemblies).Returns([assemblyMock.Object]);
@@ -94,6 +161,33 @@ public static IServiceCollection GetServices()
             return serviceCollection;
         }
     }
+    private class InvalidStartVoid
+    {
+        [ScenarioDependencies]
+        public static void GetServices()
+        {
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddSingleton<ITestInterface>(new TestInterface("ValidStartWithAutoRegister"));
+        }
+    }
+
+    private class InvalidStartNull
+    {
+        [ScenarioDependencies]
+        public static IServiceCollection GetServices()
+        {
+            return null;
+        }
+    }
+
+    private class InvalidStartWrongType
+    {
+        [ScenarioDependencies]
+        public static object GetServices()
+        {
+            return new List<string>();
+        }
+    }
     [Binding]
     private class Binding1;
 }