Add tests for AppBreadcrumb component

Fixes #8

tests/unit/app_breadcrumb.spec.js

@@ -0,0 +1,47 @@
+import AppBreadcrumb from '@/components/AppBreadcrumb.vue'
+import { RouterLinkStub, shallowMount } from '@vue/test-utils'
+
+const stubs =  {
+  RouterLink: RouterLinkStub
+}
+
+test('it returns default values', () => {
+  const wrapper = shallowMount(AppBreadcrumb, { stubs })
+
+  expect(wrapper.vm.selectedOrganisation).toBe('All')
+  expect(wrapper.vm.selectedApplication).toBe(null)
+  expect(wrapper.vm.selectedEnvironment).toBe(null)
+})
+
+test('it returns the organisation and application names', () => {
+  const wrapper = shallowMount(AppBreadcrumb, {
+    propsData: {
+      application: {
+        name: 'Oliver Davies'
+      }
+    },
+    stubs
+  })
+
+  expect(wrapper.vm.selectedOrganisation).toBe('Rebuilding Acquia')
+  expect(wrapper.vm.selectedApplication).toBe('Oliver Davies')
+  expect(wrapper.vm.selectedEnvironment).toBe('All')
+})
+
+test('it returns the environment name', () => {
+  const wrapper = shallowMount(AppBreadcrumb, {
+    propsData: {
+      application: {
+        name: 'Oliver Davies'
+      },
+      environment: {
+        name: 'Dev'
+      }
+    },
+    stubs
+  })
+
+  expect(wrapper.vm.selectedOrganisation).toBe('Rebuilding Acquia')
+  expect(wrapper.vm.selectedApplication).toBe('Oliver Davies')
+  expect(wrapper.vm.selectedEnvironment).toBe('Dev')
+})