Add unique custom field name checking

[MAILPOET-2463]

tests/javascript/form_editor/store/reducers/create_custom_field_started.spec.js

@@ -0,0 +1,46 @@
+import { expect } from 'chai';
+import reducerFactory from '../../../../../assets/js/src/form_editor/store/reducers/create_custom_field_started.jsx';
+
+const MailPoetStub = {
+  I18n: {
+    t: () => ('Error [name]!'),
+  },
+};
+const reducer = reducerFactory(MailPoetStub);
+
+const dummyCustomField = {
+  name: 'My custom field',
+};
+
+describe('Create Custom Field Started Reducer', () => {
+  let initialState = null;
+  beforeEach(() => {
+    initialState = {
+      notices: [],
+      isCustomFieldCreating: false,
+      customFields: [dummyCustomField],
+    };
+  });
+
+  it('Should set isCustomFieldCreating when there are no errors', () => {
+    const customField = { ...dummyCustomField, name: 'Unique custom field' };
+    const action = {
+      type: 'CREATE_CUSTOM_FIELD_STARTED',
+      customField,
+    };
+    const finalState = reducer(initialState, action);
+    expect(finalState.isCustomFieldCreating).to.equal(true);
+  });
+
+  it('Should create error notice and stop creation process', () => {
+    const customField = { ...dummyCustomField };
+    const action = {
+      type: 'CREATE_CUSTOM_FIELD_STARTED',
+      customField,
+    };
+    const finalState = reducer(initialState, action);
+    expect(finalState.isCustomFieldCreating).to.equal(false);
+    expect(finalState.notices.length).to.equal(1);
+    expect(finalState.notices[0].content).to.equal('Error My custom field!');
+  });
+});