fix: job serialization for interface types

Ensures correct job type resolution when enqueuing jobs that implement interfaces.

Previously, the job type was not correctly resolved when an interface was used as the type of the object containing the method to be executed. This commit updates the logic to correctly determine the underlying type of the object, ensuring proper serialization and subsequent execution of the job.

Author: VisualBean

src/ByteBard.GUSTO.JobQueue/JobQueue.cs

@@ -41,7 +41,14 @@ public TStorageRecord ConstructRecordFromExpression(Expression expression, DateT
         var methodCallExpression = (MethodCallExpression)expression;
         var method = methodCallExpression.Method;
         var arguments = methodCallExpression.Arguments.Select(arg => Expression.Lambda(arg).Compile().DynamicInvoke()).ToArray();
-        var targetType = method.DeclaringType;
+    
+        Type targetType = methodCallExpression.Object switch
+        {
+            ConstantExpression c when c.Value != null => c.Value.GetType(),
+            MemberExpression m => Expression.Lambda(m).Compile().DynamicInvoke()?.GetType() ?? method.DeclaringType,
+            _ => method.DeclaringType
+        };
+
         var record = new TStorageRecord
         {
             TrackingId = Guid.NewGuid(),

src/ByteBard.GUSTO.Tests/JobQueueTests.cs

@@ -17,14 +17,42 @@ public class TestJobStorageRecord : IJobStorageRecord
         public bool IsComplete { get; set; }
     }
 
-    private class TestJob
+    private interface ITestJob
+    {
+        Task DoSomethingAsync(string input);
+    }
+    
+    private class TestJob : ITestJob
     {
         public virtual Task DoSomethingAsync(string input)
         {
             return Task.CompletedTask;
         }
     }
 
+    [Fact]
+    public async Task EnqueueAsync_ValidInterfaceJobType_StoresSerializedJobWithRealType()
+    {
+        // Arrange
+        var storageProvider = Substitute.For<IJobStorageProvider<TestJobStorageRecord>>();
+        var jobQueue = new JobQueue<TestJobStorageRecord>(storageProvider);
+        var cancellationToken = CancellationToken.None;
+        ITestJob testJob = new TestJob();
+        
+        // Act
+        var trackingId = await jobQueue.EnqueueAsync(() => testJob.DoSomethingAsync("hello"), null, cancellationToken);
+
+        // Assert
+        await storageProvider.Received(1).StoreJobAsync(
+            Arg.Is<TestJobStorageRecord>(record =>
+                record.TrackingId == trackingId &&
+                record.MethodName == "DoSomethingAsync" &&
+                record.JobType == typeof(TestJob).AssemblyQualifiedName &&
+                JsonConvert.DeserializeObject<string[]>(record.ArgumentsJson)[0] == "hello" &&
+                !record.IsComplete),
+            cancellationToken);
+    }
+    
     [Fact]
     public async Task EnqueueAsync_ValidMethodCall_StoresSerializedJob()
     {