add an e2e-test to make sure the merge-conflict error is thrown when …

…applicable (#604)

e2e/flows/merge.e2e.js

@@ -0,0 +1,38 @@
+import { expect } from 'chai';
+import Helper from '../e2e-helper';
+
+describe('merge functionality', function () {
+  this.timeout(0);
+  const helper = new Helper();
+  after(() => {
+    helper.destroyEnv();
+  });
+  describe('re-exporting an existing version', () => {
+    let output;
+    before(() => {
+      helper.setNewLocalAndRemoteScopes();
+      helper.createComponentBarFoo();
+      helper.addComponentBarFoo();
+      helper.commitComponentBarFoo();
+      helper.exportAllComponents();
+
+      helper.reInitLocalScope();
+      helper.addRemoteScope();
+      helper.importComponent('bar/foo');
+      const scopeWithV1 = helper.cloneLocalScope();
+      helper.commitComponent('bar/foo', 'msg', '-f');
+      helper.exportAllComponents(); // v2 is exported
+
+      helper.getClonedLocalScope(scopeWithV1);
+      helper.commitComponent('bar/foo', 'msg', '-f');
+      try {
+        output = helper.exportAllComponents(); // v2 is exported again
+      } catch (e) {
+        output = e.message;
+      }
+    });
+    it('should throw merge-conflict error', () => {
+      expect(output).to.have.string('Merge conflict occurred when exporting the component');
+    });
+  });
+});