Add repo_prev_directory spec and improve a repo_file spec assertion

spec/javascripts/repo/repo_file_spec.js

@@ -102,6 +102,6 @@ describe('RepoFile', () => {
 
     vm.$el.querySelector('.repo-file-name').click();
 
-    expect(vm.linkClicked).toHaveBeenCalled();
+    expect(vm.linkClicked).toHaveBeenCalledWith(file);
   });
 });

spec/javascripts/repo/repo_prev_directory_spec.js

+import Vue from 'vue';
+import repoPrevDirectory from '~/repo/repo_prev_directory.vue';
+
+describe('RepoPrevDirectory', () => {
+  const RepoPrevDirectory = Vue.extend(repoPrevDirectory);
+
+  function createComponent(propsData) {
+    return new RepoPrevDirectory({
+      propsData,
+    }).$mount();
+  }
+
+  it('renders a prev dir link', () => {
+    const prevUrl = 'prevUrl';
+    const vm = createComponent({
+      prevUrl,
+    });
+    const link = vm.$el.querySelector('a');
+
+    spyOn(vm, 'linkClicked');
+
+    expect(link).toBeTruthy();
+    expect(link.href).toMatch(`/${prevUrl}`);
+    expect(link.textContent).toEqual('..');
+
+    link.click();
+
+    expect(vm.linkClicked).toHaveBeenCalledWith(prevUrl);
+  });
+});