Added meta data validation test to fail

IntegrationTests/Subscriber/SubscriberTestHappyPath.cs

@@ -137,4 +137,4 @@ public class SubscriberTestHappyPath : SubscriberTestBase {
         Console.WriteLine(dto.Submission.Data);
         Console.WriteLine(JsonConvert.SerializeObject(dto.Submission.Metadata));
     }
-}
+}
\ No newline at end of file

IntegrationTests/Subscriber/SubscriberTestUnHappyPath.cs

+using System.Linq;
+using FluentAssertions;
+using Microsoft.Extensions.Logging;
+using NUnit.Framework;
+
+namespace IntegrationTests.Subscriber;
+
+[TestFixture]
+public class SubscriberTestUnHappyPath : SubscriberTestBase {
+    [Test]
+    public void TestMetaData_InvalidData() {
+        // Arrange
+        var wrongData = "{\"name\":\"value\"}";
+
+        // Act
+        var validationErrors = FitConnect.Subscriber.VerifyMetadata(wrongData);
+        validationErrors.ToList().ForEach(v => Logger.LogWarning("ERROR: {V}", v.ToString()));
+
+        // Assert
+        validationErrors.Count.Should().BeGreaterThan(0);
+    }
+
+    [Test]
+    public void TestMetaData_EmptyString() {
+        // Arrange
+        var wrongData = "";
+
+        // Act && Assert
+        Assert.Throws<Newtonsoft.Json.JsonReaderException>(() => {
+            var validationErrors = FitConnect.Subscriber.VerifyMetadata(wrongData);
+            validationErrors.ToList().ForEach(v => Logger.LogWarning("ERROR: {V}", v.ToString()));
+        });
+    }
+}