fix!: Send Service Bus events as single objects instead of arrays

.githooks/commit-msg

@@ -15,16 +15,19 @@ if echo "$commit_msg" | grep -qE "^Merge "; then
     exit 0
 fi
 
-# Conventional commit pattern: type(optional scope): description
+# Conventional commit pattern: type(optional scope)(optional !): description
 # Types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert, deps
-pattern="^(feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert|deps)(\(.+\))?: .+"
+# The optional ! before the colon indicates a breaking change.
+pattern="^(feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert|deps)(\(.+\))?!?: .+"
 
 if ! echo "$commit_msg" | head -1 | grep -qE "$pattern"; then
     echo ""
     echo "ERROR: Commit message does not follow Conventional Commits format."
     echo ""
     echo "Expected format: <type>: <description>"
     echo "                 <type>(<scope>): <description>"
+    echo "                 <type>!: <description>"
+    echo "                 <type>(<scope>)!: <description>"
     echo ""
     echo "Valid types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert, deps"
     echo ""
@@ -33,8 +36,11 @@ if ! echo "$commit_msg" | head -1 | grep -qE "$pattern"; then
     echo "  fix: resolve validation error"
     echo "  docs: update README"
     echo "  chore(deps): update dependencies"
+    echo "  fix!: change Service Bus message format"
+    echo "  feat(api)!: remove deprecated endpoint"
     echo ""
     echo "Note: There must be a space after the colon."
+    echo "      Use ! before the colon to indicate a breaking change."
     echo ""
     echo "Your commit message was:"
     echo "  $(head -1 "$commit_msg_file")"

src/AzureEventGridSimulator.Tests/UnitTests/Subscribers/Delivery/ServiceBusEventDeliveryServiceTests.cs

@@ -184,7 +184,7 @@ EventSchema schema
     }
 
     [Fact]
-    public void GivenEventGridFormatter_WhenSerializing_ThenReturnsJson()
+    public void GivenEventGridFormatter_WhenSerializing_ThenReturnsJsonArray()
     {
         var formatter = _formatterFactory.GetFormatter(EventSchema.EventGridSchema);
         var evt = CreateTestEvent();
@@ -193,10 +193,12 @@ public void GivenEventGridFormatter_WhenSerializing_ThenReturnsJson()
 
         json.ShouldNotBeNullOrEmpty();
         json.ShouldContain("test-event-id");
+        json.TrimStart().ShouldStartWith("[");
+        json.TrimEnd().ShouldEndWith("]");
     }
 
     [Fact]
-    public void GivenCloudEventFormatter_WhenSerializing_ThenReturnsJson()
+    public void GivenCloudEventFormatter_WhenSerializing_ThenReturnsJsonArray()
     {
         var formatter = _formatterFactory.GetFormatter(EventSchema.CloudEventV1_0);
         var evt = CreateTestEvent();
@@ -205,6 +207,8 @@ public void GivenCloudEventFormatter_WhenSerializing_ThenReturnsJson()
 
         json.ShouldNotBeNullOrEmpty();
         json.ShouldContain("test-event-id");
+        json.TrimStart().ShouldStartWith("[");
+        json.TrimEnd().ShouldEndWith("]");
     }
 
     [Fact]
@@ -248,4 +252,34 @@ public void GivenPropertyResolver_WhenResolvingDynamicProperty_ThenReturnsEventV
 
         resolved["Subject"].ShouldBe("test/subject");
     }
+
+    [Fact]
+    public void GivenCloudEventFormatter_WhenSerializingSingle_ThenReturnsJsonWithoutArray()
+    {
+        var formatter = _formatterFactory.GetFormatter(EventSchema.CloudEventV1_0);
+        var evt = CreateTestEvent();
+
+        var json = formatter.SerializeSingle(evt);
+
+        json.ShouldNotBeNullOrEmpty();
+        json.ShouldContain("test-event-id");
+        // Verify it's NOT an array (doesn't start with '[')
+        json.TrimStart().ShouldStartWith("{");
+        json.TrimEnd().ShouldEndWith("}");
+    }
+
+    [Fact]
+    public void GivenEventGridFormatter_WhenSerializingSingle_ThenReturnsJsonWithoutArray()
+    {
+        var formatter = _formatterFactory.GetFormatter(EventSchema.EventGridSchema);
+        var evt = CreateTestEvent();
+
+        var json = formatter.SerializeSingle(evt);
+
+        json.ShouldNotBeNullOrEmpty();
+        json.ShouldContain("test-event-id");
+        // Verify it's NOT an array (doesn't start with '[')
+        json.TrimStart().ShouldStartWith("{");
+        json.TrimEnd().ShouldEndWith("}");
+    }
 }

src/AzureEventGridSimulator/Domain/Services/CloudEventSchemaFormatter.cs

@@ -33,6 +33,13 @@ public string Serialize(SimulatorEvent evt)
         return JsonSerializer.Serialize(new[] { cloudEvent }, _serializerOptions);
     }
 
+    /// <inheritdoc />
+    public string SerializeSingle(SimulatorEvent evt)
+    {
+        var cloudEvent = ConvertToCloudEvent(evt);
+        return JsonSerializer.Serialize(cloudEvent, _serializerOptions);
+    }
+
     /// <inheritdoc />
     public string SerializeArray(IEnumerable<SimulatorEvent> events)
     {

src/AzureEventGridSimulator/Domain/Services/Delivery/ServiceBusEventDeliveryService.cs

@@ -58,8 +58,8 @@ CancellationToken cancellationToken
                 subscription.DeliverySchema ?? delivery.Topic.OutputSchema ?? delivery.InputSchema;
             var formatter = formatterFactory.GetFormatter(deliverySchema);
 
-            // Serialize the event
-            var json = formatter.Serialize(delivery.Event);
+            // Serialize as a single event (matches Azure Event Grid to Service Bus behavior)
+            var json = formatter.SerializeSingle(delivery.Event);
 
             // Get or create the sender
             var sender = GetOrCreateSender(subscription);
@@ -171,8 +171,8 @@ EventSchema inputSchema
             var deliverySchema = subscription.DeliverySchema ?? topic.OutputSchema ?? inputSchema;
             var formatter = formatterFactory.GetFormatter(deliverySchema);
 
-            // Serialize the event
-            var json = formatter.Serialize(evt);
+            // Serialize as a single event (matches Azure Event Grid to Service Bus behavior)
+            var json = formatter.SerializeSingle(evt);
 
             // Get or create the sender
             var sender = GetOrCreateSender(subscription);

src/AzureEventGridSimulator/Domain/Services/EventGridSchemaFormatter.cs

@@ -21,6 +21,13 @@ public string Serialize(SimulatorEvent evt)
         return JsonSerializer.Serialize(new[] { eventGridEvent });
     }
 
+    /// <inheritdoc />
+    public string SerializeSingle(SimulatorEvent evt)
+    {
+        var eventGridEvent = ConvertToEventGridEvent(evt);
+        return JsonSerializer.Serialize(eventGridEvent);
+    }
+
     /// <inheritdoc />
     public string SerializeArray(IEnumerable<SimulatorEvent> events)
     {

src/AzureEventGridSimulator/Domain/Services/IEventSchemaFormatter.cs

@@ -19,6 +19,7 @@ public interface IEventSchemaFormatter
 
     /// <summary>
     ///     Serializes an event to JSON for delivery.
+    ///     By default, wraps single events in an array for Azure Event Grid compatibility.
     /// </summary>
     /// <param name="evt">
     ///     The event to serialize.
@@ -28,6 +29,18 @@ public interface IEventSchemaFormatter
     /// </returns>
     string Serialize(SimulatorEvent evt);
 
+    /// <summary>
+    ///     Serializes a single event to JSON without array wrapper.
+    ///     Used for Service Bus delivery which doesn't use array format.
+    /// </summary>
+    /// <param name="evt">
+    ///     The event to serialize.
+    /// </param>
+    /// <returns>
+    ///     The JSON representation of the single event.
+    /// </returns>
+    string SerializeSingle(SimulatorEvent evt);
+
     /// <summary>
     ///     Serializes multiple events to JSON for delivery.
     /// </summary>

src/Directory.Packages.props

@@ -34,7 +34,7 @@
         <PackageVersion Include="OpenTelemetry.Instrumentation.Http" Version="1.15.0" />
         <PackageVersion Include="OpenTelemetry.Instrumentation.Runtime" Version="1.15.0" />
         <!-- Analyzers -->
-        <PackageVersion Include="Meziantou.Analyzer" Version="2.0.302" />
+        <PackageVersion Include="Meziantou.Analyzer" Version="3.0.1" />
         <!-- Conformance Testing CLI -->
         <PackageVersion Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
         <!-- Testing -->
@@ -44,6 +44,6 @@
         <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
         <PackageVersion Include="xunit" Version="2.9.3" />
         <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
-        <PackageVersion Include="coverlet.collector" Version="6.0.4" />
+        <PackageVersion Include="coverlet.collector" Version="8.0.0" />
     </ItemGroup>
 </Project>