diff --git a/UNRELEASED.md b/UNRELEASED.md
index 9154ae3a2b2..926214c7f0d 100644
--- a/UNRELEASED.md
+++ b/UNRELEASED.md
@@ -41,5 +41,6 @@ Use [the changelog guidelines](https://git.io/polaris-changelog-guidelines) to f
 - Modernized tests for FormLayout and some components of ColorPicker ([#4330](https://github.com/Shopify/polaris-react/pull/4330))
 - Modernized tests for Breadcrumbs, BulkActions, Button, ButtonGroup/Item, and ButtonGroup components([#4315](https://github.com/Shopify/polaris-react/pull/4315))
 - Modernized tests for DualThumb ([#4341](https://github.com/Shopify/polaris-react/pull/4341))
+- Modernized tests for AppProvider, AfterInitialMount components([#4315](https://github.com/Shopify/polaris-react/pull/4331))
 
 ### Deprecations
diff --git a/src/components/AfterInitialMount/test/AfterInitialMount.test.tsx b/src/components/AfterInitialMount/test/AfterInitialMount.test.tsx
index c6afab0f23e..a87aae29d47 100644
--- a/src/components/AfterInitialMount/test/AfterInitialMount.test.tsx
+++ b/src/components/AfterInitialMount/test/AfterInitialMount.test.tsx
@@ -1,5 +1,5 @@
 import React, {useEffect} from 'react';
-import {mount} from 'test-utilities';
+import {mountWithApp} from 'test-utilities/react-testing';
 
 import {AfterInitialMount} from '../AfterInitialMount';
 
@@ -12,7 +12,7 @@ describe('AfterInitialMount', () => {
       return null;
     }
 
-    mount(<AfterInitialMount fallback={<Fallback />} />);
+    mountWithApp(<AfterInitialMount fallback={<Fallback />} />);
     expect(spy).toHaveBeenCalledTimes(1);
   });
 
@@ -31,7 +31,7 @@ describe('AfterInitialMount', () => {
       return null;
     }
 
-    const afterInitialMount = mount(
+    const afterInitialMount = mountWithApp(
       <AfterInitialMount fallback={<Fallback />}>
         <Children />
       </AfterInitialMount>,
diff --git a/src/components/AppProvider/tests/AppProvider.test.tsx b/src/components/AppProvider/tests/AppProvider.test.tsx
index 5628bd9e879..60b59f194de 100644
--- a/src/components/AppProvider/tests/AppProvider.test.tsx
+++ b/src/components/AppProvider/tests/AppProvider.test.tsx
@@ -1,7 +1,5 @@
 import React, {useContext} from 'react';
 import {matchMedia} from '@shopify/jest-dom-mocks';
-// eslint-disable-next-line no-restricted-imports
-import {mountWithAppProvider} from 'test-utilities/legacy';
 import {mountWithApp} from 'test-utilities/react-testing';
 import {MediaQueryProvider} from 'components/MediaQueryProvider';
 
@@ -19,21 +17,21 @@ describe('<AppProvider />', () => {
   });
 
   it('updates context when props change', () => {
-    const Child: React.SFC = () => {
+    const Child: React.FunctionComponent = () => {
       return useContext(LinkContext) ? <div id="child" /> : null;
     };
     const LinkComponent = () => <div />;
 
-    const wrapper = mountWithAppProvider(
+    const wrapper = mountWithApp(
       <AppProvider i18n={{}}>
         <Child />
       </AppProvider>,
     );
 
-    expect(wrapper.find('#child')).toHaveLength(0);
+    expect(wrapper).not.toContainReactComponent('div', {id: 'child'});
     wrapper.setProps({linkComponent: LinkComponent});
-    wrapper.update();
-    expect(wrapper.find('#child')).toHaveLength(1);
+    wrapper.forceUpdate();
+    expect(wrapper).toContainReactComponent('div', {id: 'child'});
   });
 
   it('renders a MediaProvider', () => {
diff --git a/src/components/IndexTable/IndexTable.scss b/src/components/IndexTable/IndexTable.scss
index 5f5ccd43232..a41a135584e 100644
--- a/src/components/IndexTable/IndexTable.scss
+++ b/src/components/IndexTable/IndexTable.scss
@@ -148,6 +148,7 @@ $loading-panel-height: rem(53px);
     }
   }
 
+  // stylelint-disable-next-line selector-max-class
   &.TableRow-hovered.TableRow-selected {
     // stylelint-disable-next-line selector-max-class, selector-max-combinators, selector-max-specificity
     &,