fix(rules): always allow copying labels

* basic copy rules are implemented in diagram-js CopyPaste e.g. labels can only be copied when their label target is copied

Closes #1153

lib/features/rules/BpmnRules.js

@@ -895,6 +895,10 @@ function includes(elements, element) {
 }
 
 function canCopy(elements, element) {
+  if (isLabel(element)) {
+    return true;
+  }
+
   if (is(element, 'bpmn:Lane') && !includes(elements, element.parent)) {
     return false;
   }

test/spec/features/rules/BpmnRulesSpec.js

@@ -5,10 +5,11 @@ import {
 
 import {
   expectCanConnect,
+  expectCanCopy,
+  expectCanCreate,
   expectCanDrop,
-  expectCanMove,
   expectCanInsert,
-  expectCanCreate
+  expectCanMove
 } from './Helper';
 
 import modelingModule from 'lib/features/modeling';
@@ -83,6 +84,81 @@ describe('features/modeling/rules - BpmnRules', function() {
   });
 
 
+  describe('copy elements', function() {
+
+    var testXML = require('./BpmnRules.process.bpmn');
+
+    beforeEach(bootstrapModeler(testXML, { modules: testModules }));
+
+
+    it('copy task', inject(function(elementFactory) {
+
+      // given
+      var task1 = elementFactory.createShape({ type: 'bpmn:Task' });
+
+      // then
+      expectCanCopy(task1, [ task1 ], true);
+    }));
+
+
+    it('copy label', inject(function(elementFactory) {
+
+      // given
+      var task = elementFactory.createShape({ type: 'bpmn:Task' }),
+          label = elementFactory.createLabel({ labelTarget: task });
+
+      // then
+      // copying labels should always be allowed
+      expectCanCopy(label, [], true);
+    }));
+
+
+    it('copy lane with parent participant', inject(function(elementFactory) {
+
+      // given
+      var participant = elementFactory.createShape({ type: 'bpmn:Participant' }),
+          lane = elementFactory.createShape({ type: 'bpmn:Lane', parent: participant });
+
+      // then
+      expectCanCopy(lane, [ participant ], true);
+    }));
+
+
+    it('copy lane without parent participant', inject(function(elementFactory) {
+
+      // given
+      var participant = elementFactory.createShape({ type: 'bpmn:Participant' }),
+          lane = elementFactory.createShape({ type: 'bpmn:Lane', parent: participant });
+
+      // then
+      expectCanCopy(lane, [], false);
+    }));
+
+
+    it('copy boundary event with host', inject(function(elementFactory) {
+
+      // given
+      var task = elementFactory.createShape({ type: 'bpmn:Task' }),
+          boundaryEvent = elementFactory.createShape({ type: 'bpmn:BoundaryEvent', host: task });
+
+      // then
+      expectCanCopy(boundaryEvent, [ task ], true);
+    }));
+
+
+    it('copy boundary event without host', inject(function(elementFactory) {
+
+      // given
+      var task = elementFactory.createShape({ type: 'bpmn:Task' }),
+          boundaryEvent = elementFactory.createShape({ type: 'bpmn:BoundaryEvent', host: task });
+
+      // then
+      expectCanCopy(boundaryEvent, [], false);
+    }));
+
+  });
+
+
   describe('on process diagram', function() {
 
     var testXML = require('./BpmnRules.process.bpmn');

test/spec/features/rules/Helper.js

@@ -70,6 +70,19 @@ export function expectCanCreate(shape, target, expectedResult) {
 }
 
 
+export function expectCanCopy(element, elements, expectedResult) {
+
+  var result = getBpmnJS().invoke(function(rules) {
+    return rules.allowed('element.copy', {
+      element: element,
+      elements: elements
+    });
+  });
+
+  expect(result).to.eql(expectedResult);
+}
+
+
 export function expectCanInsert(element, target, expectedResult) {
 
   var result = getBpmnJS().invoke(function(bpmnRules) {