Added specs for description field

spec/javascripts/issue_show/components/fields/description_spec.js

+import Vue from 'vue';
+import Store from '~/issue_show/stores';
+import descriptionField from '~/issue_show/components/fields/description.vue';
+
+describe('Description field component', () => {
+  let vm;
+  let store;
+
+  beforeEach((done) => {
+    const Component = Vue.extend(descriptionField);
+    store = new Store({
+      titleHtml: '',
+      descriptionHtml: '',
+      issuableRef: '',
+    });
+    store.formState.description = 'test';
+
+    vm = new Component({
+      propsData: {
+        markdownPreviewUrl: '/',
+        markdownDocs: '/',
+        store,
+      },
+    }).$mount();
+
+    Vue.nextTick(done);
+  });
+
+  it('renders markdown field with description', () => {
+    expect(
+      vm.$el.querySelector('.md-area textarea').value,
+    ).toBe('test');
+  });
+});

spec/javascripts/vue_shared/components/markdown/field_spec.js

+import Vue from 'vue';
+import fieldComponent from '~/vue_shared/components/markdown/field.vue';
+
+describe('Markdown field component', () => {
+  let vm;
+
+  beforeEach(() => {
+    vm = new Vue({
+      render(createElement) {
+        return createElement(
+          fieldComponent,
+          {
+            props: {
+              markdownPreviewUrl: '/preview',
+              markdownDocs: '/docs',
+            },
+          },
+          [
+            createElement('textarea', {
+              slot: 'textarea',
+            }),
+          ],
+        );
+      },
+    });
+  });
+
+  it('creates a new instance of GL form', (done) => {
+    spyOn(gl, 'GLForm');
+    vm.$mount();
+
+    Vue.nextTick(() => {
+      expect(
+        gl.GLForm,
+      ).toHaveBeenCalled();
+
+      done();
+    });
+  });
+
+  describe('mounted', () => {
+    beforeEach((done) => {
+      vm.$mount();
+
+      Vue.nextTick(done);
+    });
+
+    it('renders textarea inside backdrop', () => {
+      expect(
+        vm.$el.querySelector('.zen-backdrop textarea'),
+      ).not.toBeNull();
+    });
+
+    describe('markdown preview', () => {
+      let previewLink;
+
+      beforeEach(() => {
+        spyOn(Vue.http, 'post').and.callFake(() => new Promise((resolve) => {
+          resolve({
+            json() {
+              return {
+                body: '<p>markdown preview</p>',
+              };
+            },
+          });
+        }));
+
+        previewLink = vm.$el.querySelector('.nav-links li:nth-child(2) a');
+      });
+
+      it('sets preview link as active', (done) => {
+        previewLink.click();
+
+        Vue.nextTick(() => {
+          expect(
+            previewLink.parentNode.classList.contains('active'),
+          ).toBeTruthy();
+
+          done();
+        });
+      });
+
+      it('shows preview loading text', (done) => {
+        previewLink.click();
+
+        Vue.nextTick(() => {
+          expect(
+            vm.$el.querySelector('.md-preview').textContent.trim(),
+          ).toContain('Loading...');
+
+          done();
+        });
+      });
+
+      it('renders markdown preview', (done) => {
+        previewLink.click();
+
+        setTimeout(() => {
+          expect(
+            vm.$el.querySelector('.md-preview').innerHTML,
+          ).toContain('<p>markdown preview</p>');
+
+          done();
+        });
+      });
+
+      it('renders GFM with jQuery', (done) => {
+        spyOn($.fn, 'renderGFM');
+        previewLink.click();
+
+        setTimeout(() => {
+          expect(
+            $.fn.renderGFM,
+          ).toHaveBeenCalled();
+
+          done();
+        });
+      });
+    });
+  });
+});

spec/javascripts/vue_shared/components/markdown/header_spec.js

+import Vue from 'vue';
+import headerComponent from '~/vue_shared/components/markdown/header.vue';
+
+describe('Markdown field header component', () => {
+  let vm;
+
+  beforeEach((done) => {
+    const Component = Vue.extend(headerComponent);
+
+    vm = new Component({
+      propsData: {
+        previewMarkdown: false,
+      },
+    }).$mount();
+
+    Vue.nextTick(done);
+  });
+
+  it('renders markdown buttons', () => {
+    expect(
+      vm.$el.querySelectorAll('.js-md').length,
+    ).toBe(7);
+  });
+
+  it('renders `write` link as active when previewMarkdown is false', () => {
+    expect(
+      vm.$el.querySelector('li:nth-child(1)').classList.contains('active'),
+    ).toBeTruthy();
+  });
+
+  it('renders `preview` link as active when previewMarkdown is true', (done) => {
+    vm.previewMarkdown = true;
+
+    Vue.nextTick(() => {
+      expect(
+        vm.$el.querySelector('li:nth-child(2)').classList.contains('active'),
+      ).toBeTruthy();
+
+      done();
+    });
+  });
+
+  it('emits toggle markdown event when clicking preview', () => {
+    spyOn(vm, '$emit');
+
+    vm.$el.querySelector('li:nth-child(2) a').click();
+
+    expect(
+      vm.$emit,
+    ).toHaveBeenCalledWith('toggle-markdown');
+  });
+
+  it('blurs preview link after click', (done) => {
+    const link = vm.$el.querySelector('li:nth-child(2) a');
+    spyOn(HTMLElement.prototype, 'blur');
+
+    link.click();
+
+    setTimeout(() => {
+      expect(
+        link.blur,
+      ).toHaveBeenCalled();
+
+      done();
+    });
+  });
+});