fix: Add formatSSEEvent method for cross-engine test compatibility

The SSE format test was failing on Lucee because savecontent doesn't
capture writeOutput from nested method calls. Added formatSSEEvent()
method that returns the formatted string directly, which streamEvent()
now uses internally. Tests now call formatSSEEvent() directly instead
of relying on savecontent to capture writeOutput.

Author: elpete

system/util/StreamingService.cfc

@@ -35,6 +35,19 @@ component accessors="true" {
 		return this;
 	}
 
+	/**
+	 * Format an SSE event as a string
+	 * Returns the properly formatted SSE event string without writing to output
+	 *
+	 * @eventType The type of event (e.g., bundleStart, specEnd)
+	 * @data      The data payload to serialize as JSON
+	 *
+	 * @return string The formatted SSE event string
+	 */
+	string function formatSSEEvent( required string eventType, required any data ){
+		return "event: #arguments.eventType##chr( 10 )#data: #serializeJSON( arguments.data )##chr( 10 )##chr( 10 )#";
+	}
+
 	/**
 	 * Stream an SSE event to the client
 	 * Errors are caught and logged to prevent client disconnects from interrupting test execution.
@@ -44,8 +57,7 @@ component accessors="true" {
 	 */
 	function streamEvent( required string eventType, required any data ){
 		try {
-			writeOutput( "event: #arguments.eventType##chr( 10 )#" );
-			writeOutput( "data: #serializeJSON( arguments.data )##chr( 10 )##chr( 10 )#" );
+			writeOutput( formatSSEEvent( arguments.eventType, arguments.data ) );
 			// Only flush if enabled (disabled during unit testing to prevent response commit)
 			if ( isNull( variables.flushEnabled ) || variables.flushEnabled ) {
 				cfflush(  );

tests/specs/streaming/StreamingServiceTest.cfc

@@ -51,18 +51,10 @@ component extends="testbox.system.BaseSpec" {
 			} );
 
 			describe( "SSE event format", function(){
-				it( "streamEvent produces correct SSE format string", function(){
-					// Disable flushing to prevent response commit during testing
-					variables.streamingService.setFlushEnabled( false );
-
-					// Capture the actual output from streamEvent using savecontent
+				it( "formatSSEEvent produces correct SSE format string", function(){
 					var eventType = "testEvent";
 					var data      = { "key" : "value" };
-					var output    = "";
-
-					savecontent variable="output" {
-						variables.streamingService.streamEvent( eventType, data );
-					}
+					var output    = variables.streamingService.formatSSEEvent( eventType, data );
 
 					// Verify SSE format: event: <type>\ndata: <json>\n\n
 					expect( output ).toInclude( "event: testEvent" );
@@ -71,21 +63,14 @@ component extends="testbox.system.BaseSpec" {
 					expect( right( output, 2 ) ).toBe( chr( 10 ) & chr( 10 ) );
 				} );
 
-				it( "streamEvent serializes complex data to JSON correctly", function(){
-					// Disable flushing to prevent response commit during testing
-					variables.streamingService.setFlushEnabled( false );
-
+				it( "formatSSEEvent serializes complex data to JSON correctly", function(){
 					var testData = {
 						"id"       : "test-123",
 						"name"     : "Test Spec",
 						"nested"   : { "foo" : "bar" },
 						"arrayVal" : [ 1, 2, 3 ]
 					};
-					var output = "";
-
-					savecontent variable="output" {
-						variables.streamingService.streamEvent( "testEvent", testData );
-					}
+					var output = variables.streamingService.formatSSEEvent( "testEvent", testData );
 
 					expect( output ).toInclude( """id""" );
 					expect( output ).toInclude( """test-123""" );