1 files changed, 145 insertions, 0 deletions
diff --git a/spec/frontend/vue_shared/components/ensure_data_spec.js b/spec/frontend/vue_shared/components/ensure_data_spec.js
new file mode 100644
index 00000000000..eef8b452f5f
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+++ b/spec/frontend/vue_shared/components/ensure_data_spec.js
@@ -0,0 +1,145 @@
+import { GlEmptyState } from '@gitlab/ui';
+import * as Sentry from '@sentry/browser';
+import { mount } from '@vue/test-utils';
+import ensureData from '~/ensure_data';
+
+const mockData = { message: 'Hello there' };
+const defaultOptions = {
+  parseData: () => mockData,
+  data: mockData,
+};
+
+const MockChildComponent = {
+  inject: ['message'],
+  render(createElement) {
+    return createElement('h1', this.message);
+  },
+};
+
+const MockParentComponent = {
+  components: {
+    MockChildComponent,
+  },
+  props: {
+    message: {
+      type: String,
+      required: true,
+    },
+    otherProp: {
+      type: Boolean,
+      default: false,
+      required: false,
+    },
+  },
+  render(createElement) {
+    return createElement('div', [this.message, createElement(MockChildComponent)]);
+  },
+};
+
+describe('EnsureData', () => {
+  let wrapper;
+
+  function findEmptyState() {
+    return wrapper.findComponent(GlEmptyState);
+  }
+
+  function findChild() {
+    return wrapper.findComponent(MockChildComponent);
+  }
+  function findParent() {
+    return wrapper.findComponent(MockParentComponent);
+  }
+
+  function createComponent(options = defaultOptions) {
+    return mount(ensureData(MockParentComponent, options));
+  }
+
+  beforeEach(() => {
+    Sentry.captureException = jest.fn();
+  });
+
+  afterEach(() => {
+    wrapper.destroy();
+    Sentry.captureException.mockClear();
+  });
+
+  describe('when parseData throws', () => {
+    it('should render GlEmptyState', () => {
+      wrapper = createComponent({
+        parseData: () => {
+          throw new Error();
+        },
+      });
+
+      expect(findParent().exists()).toBe(false);
+      expect(findChild().exists()).toBe(false);
+      expect(findEmptyState().exists()).toBe(true);
+    });
+
+    it('should not log to Sentry when shouldLog=false (default)', () => {
+      wrapper = createComponent({
+        parseData: () => {
+          throw new Error();
+        },
+      });
+
+      expect(Sentry.captureException).not.toHaveBeenCalled();
+    });
+
+    it('should log to Sentry when shouldLog=true', () => {
+      const error = new Error('Error!');
+      wrapper = createComponent({
+        parseData: () => {
+          throw error;
+        },
+        shouldLog: true,
+      });
+
+      expect(Sentry.captureException).toHaveBeenCalledWith(error);
+    });
+  });
+
+  describe('when parseData succeeds', () => {
+    it('should render MockParentComponent and MockChildComponent', () => {
+      wrapper = createComponent();
+
+      expect(findEmptyState().exists()).toBe(false);
+      expect(findParent().exists()).toBe(true);
+      expect(findChild().exists()).toBe(true);
+    });
+
+    it('enables user to provide data to child components', () => {
+      wrapper = createComponent();
+
+      const childComponent = findChild();
+      expect(childComponent.text()).toBe(mockData.message);
+    });
+
+    it('enables user to override provide data', () => {
+      const message = 'Another message';
+      wrapper = createComponent({ ...defaultOptions, provide: { message } });
+
+      const childComponent = findChild();
+      expect(childComponent.text()).toBe(message);
+    });
+
+    it('enables user to pass props to parent component', () => {
+      wrapper = createComponent();
+
+      expect(findParent().props()).toMatchObject(mockData);
+    });
+
+    it('enables user to override props data', () => {
+      const props = { message: 'Another message', otherProp: true };
+      wrapper = createComponent({ ...defaultOptions, props });
+
+      expect(findParent().props()).toMatchObject(props);
+    });
+
+    it('should not log to Sentry when shouldLog=true', () => {
+      wrapper = createComponent({ ...defaultOptions, shouldLog: true });
+
+      expect(Sentry.captureException).not.toHaveBeenCalled();
+    });
+  });
+});