fix(modeling): create ConditionalEventDefinition with condition

This ensures we always create valid BPMN 2.0 XML when
creating conditional start and intermediate events.

Closes #747

lib/features/modeling/ElementFactory.js

@@ -103,6 +103,10 @@ ElementFactory.prototype.createBpmnElement = function(elementType, attrs) {
     eventDefinitions = businessObject.get('eventDefinitions') || [];
     newEventDefinition = this._moddle.create(attrs.eventDefinitionType);
 
+    if (attrs.eventDefinitionType === 'bpmn:ConditionalEventDefinition') {
+      newEventDefinition.condition = this._moddle.create('bpmn:FormalExpression');
+    }
+
     eventDefinitions.push(newEventDefinition);
 
     newEventDefinition.$parent = businessObject;

test/spec/features/replace/BpmnReplaceSpec.js

@@ -1226,7 +1226,8 @@ describe('features/replace - bpmn replace', function() {
     }));
 
 
-    it('should properly set parent of event definitions', inject(function(elementRegistry, modeling, bpmnReplace) {
+    it('should properly set parent of event definitions', inject(
+      function(elementRegistry, modeling, bpmnReplace) {
 
         var startEvent = elementRegistry.get('StartEvent_1');
 
@@ -1239,7 +1240,27 @@ describe('features/replace - bpmn replace', function() {
 
         expect(parent).to.exist;
         expect(parent).to.equal(messageEvent.businessObject);
-    }));
+      })
+    );
+
+
+    it('should add condition with ConditionalEventDefinition', inject(
+      function(elementRegistry, modeling, bpmnReplace) {
+
+        var startEvent = elementRegistry.get('StartEvent_1');
+
+        // when
+        var messageEvent = bpmnReplace.replaceElement(startEvent, {
+          type: 'bpmn:StartEvent',
+          eventDefinitionType: 'bpmn:ConditionalEventDefinition'
+        });
+
+        var definition = messageEvent.businessObject.eventDefinitions[0];
+
+        // then
+        expect(definition.condition).to.exist;
+      })
+    );
 
   });