1 files changed, 52 insertions, 0 deletions
diff --git a/spec/frontend/monitoring/components/variables/custom_variable_spec.js b/spec/frontend/monitoring/components/variables/custom_variable_spec.js
new file mode 100644
index 00000000000..5a2b26219b6
--- /dev/null
+++ b/spec/frontend/monitoring/components/variables/custom_variable_spec.js
@@ -0,0 +1,52 @@
+import { shallowMount } from '@vue/test-utils';
+import { GlDropdown, GlDropdownItem } from '@gitlab/ui';
+import CustomVariable from '~/monitoring/components/variables/custom_variable.vue';
+
+describe('Custom variable component', () => {
+  let wrapper;
+  const propsData = {
+    name: 'env',
+    label: 'Select environment',
+    value: 'Production',
+    options: [{ text: 'Production', value: 'prod' }, { text: 'Canary', value: 'canary' }],
+  };
+  const createShallowWrapper = () => {
+    wrapper = shallowMount(CustomVariable, {
+      propsData,
+    });
+  };
+
+  const findDropdown = () => wrapper.find(GlDropdown);
+  const findDropdownItems = () => wrapper.findAll(GlDropdownItem);
+
+  it('renders dropdown element when all necessary props are passed', () => {
+    createShallowWrapper();
+
+    expect(findDropdown()).toExist();
+  });
+
+  it('renders dropdown element with a text', () => {
+    createShallowWrapper();
+
+    expect(findDropdown().attributes('text')).toBe(propsData.value);
+  });
+
+  it('renders all the dropdown items', () => {
+    createShallowWrapper();
+
+    expect(findDropdownItems()).toHaveLength(propsData.options.length);
+  });
+
+  it('changing dropdown items triggers update', () => {
+    createShallowWrapper();
+    jest.spyOn(wrapper.vm, '$emit');
+
+    findDropdownItems()
+      .at(1)
+      .vm.$emit('click');
+
+    return wrapper.vm.$nextTick(() => {
+      expect(wrapper.vm.$emit).toHaveBeenCalledWith('onUpdate', 'env', 'canary');
+    });
+  });
+});