Use `mockImportedComponents` in several additional tests

For consistency with other tests, use `mockImportedComponents` so that
an issue with an imported component doesn't cause a cascade of failures
in the unit tests for these components.

src/sidebar/components/test/markdown-editor-test.js

@@ -6,6 +6,7 @@ import { LinkType } from '../../markdown-commands';
 import MarkdownEditor from '../markdown-editor';
 import { $imports } from '../markdown-editor';
 
+import mockImportedComponents from '../../../test-util/mock-imported-components';
 import { checkAccessibility } from '../../../test-util/accessibility';
 
 describe('MarkdownEditor', () => {
@@ -32,6 +33,7 @@ describe('MarkdownEditor', () => {
       return null;
     };
 
+    $imports.$mock(mockImportedComponents());
     $imports.$mock({
       '../markdown-commands': fakeMarkdownCommands,
       './markdown-view': MarkdownView,

src/sidebar/components/test/search-input-test.js

@@ -4,6 +4,7 @@ import { createElement } from 'preact';
 import SearchInput from '../search-input';
 import { $imports } from '../search-input';
 
+import mockImportedComponents from '../../../test-util/mock-imported-components';
 import { checkAccessibility } from '../../../test-util/accessibility';
 
 describe('SearchInput', () => {
@@ -22,11 +23,8 @@ describe('SearchInput', () => {
   beforeEach(() => {
     fakeStore = { isLoading: sinon.stub().returns(false) };
 
-    const FakeSpinner = () => null;
-    FakeSpinner.displayName = 'Spinner';
-
+    $imports.$mock(mockImportedComponents());
     $imports.$mock({
-      './spinner': FakeSpinner,
       '../store/use-store': callback => callback(fakeStore),
     });
   });
@@ -84,7 +82,7 @@ describe('SearchInput', () => {
   it('renders search button when app is not in "loading" state', () => {
     fakeStore.isLoading.returns(false);
     const wrapper = createSearchInput();
-    assert.isTrue(wrapper.exists('button'));
+    assert.isTrue(wrapper.exists('Button'));
   });
 
   it(

src/sidebar/components/test/version-info-test.js

@@ -4,6 +4,7 @@ import { createElement } from 'preact';
 import VersionInfo from '../version-info';
 import { $imports } from '../version-info';
 
+import mockImportedComponents from '../../../test-util/mock-imported-components';
 import { checkAccessibility } from '../../../test-util/accessibility';
 
 describe('VersionInfo', function () {
@@ -32,6 +33,7 @@ describe('VersionInfo', function () {
     fakeCopyToClipboard = {
       copyText: sinon.stub(),
     };
+    $imports.$mock(mockImportedComponents());
     $imports.$mock({
       '../util/copy-to-clipboard': fakeCopyToClipboard,
     });
@@ -65,7 +67,7 @@ describe('VersionInfo', function () {
     it('copies version info to clipboard when copy button clicked', () => {
       const wrapper = createComponent();
 
-      wrapper.find('button').simulate('click');
+      wrapper.find('Button').props().onClick();
 
       assert.calledWith(fakeCopyToClipboard.copyText, 'fakeString');
     });
@@ -73,7 +75,7 @@ describe('VersionInfo', function () {
     it('confirms info copy when successful', () => {
       const wrapper = createComponent();
 
-      wrapper.find('button').simulate('click');
+      wrapper.find('Button').props().onClick();
 
       assert.calledWith(
         fakeToastMessenger.success,
@@ -85,7 +87,7 @@ describe('VersionInfo', function () {
       fakeCopyToClipboard.copyText.throws();
       const wrapper = createComponent();
 
-      wrapper.find('button').simulate('click');
+      wrapper.find('Button').props().onClick();
 
       assert.calledWith(
         fakeToastMessenger.error,