diff --git a/src/app/helpers/errata.ts b/src/app/helpers/errata.ts
index 9604f3be6..bd95c4ab9 100644
--- a/src/app/helpers/errata.ts
+++ b/src/app/helpers/errata.ts
@@ -18,7 +18,7 @@ export type Errata = {
     resolutionNotes: string;
 };
 
-type Detail = Pick<
+export type Detail = Pick<
     Errata,
     'id' | 'status' | 'errorType' | 'detail' | 'resolutionNotes'
 > & {
diff --git a/src/app/pages/errata-detail/detail/detail.js b/src/app/pages/errata-detail/detail/detail.js
deleted file mode 100644
index dc1cbd342..000000000
--- a/src/app/pages/errata-detail/detail/detail.js
+++ /dev/null
@@ -1,63 +0,0 @@
-import React from 'react';
-import RawHTML from '~/components/jsx-helpers/raw-html';
-import {useErrataDetail, shouldShowDecisionDetails} from '~/helpers/errata';
-import './detail.scss';
-
-const detailDataPairs = [
-    ['Submission ID', 'id'],
-    ['Title', 'bookTitle'],
-    ['Source', 'source'],
-    ['Status', 'status'],
-    ['Error Type', 'errorType'],
-    ['Location', 'location'],
-    ['Description', 'detail'],
-    ['Date Submitted', 'date']
-];
-const decisionDataPairs = [
-    ['Decision', 'resolutionNotes']
-];
-
-function LabelValuePairs({detail, pairs}) {
-    return (
-        <React.Fragment>
-            {
-                pairs.map((pair) =>
-                    <div className="label-value-pair" key={pair[0]}>
-                        <div className="label">{pair[0]}</div>
-                        <RawHTML className="value" html={detail[pair[1]] || ''} />
-                    </div>
-                )
-            }
-        </React.Fragment>
-    );
-}
-
-export default function Detail({data}) {
-    const detail = useErrataDetail(data);
-
-    if (!detail) {
-        return null;
-    }
-    const showDecisionDetails = shouldShowDecisionDetails(data);
-
-    return (
-        <React.Fragment>
-            {
-                showDecisionDetails &&
-                    <div className="info body-block graybottom">
-                        <LabelValuePairs detail={detail} pairs={decisionDataPairs} />
-                    </div>
-            }
-            <div className="info body-block">
-                <LabelValuePairs detail={detail} pairs={detailDataPairs} />
-            </div>
-            <div className="note">
-                {'You can check the status of all errata submissions on the '}
-                <a href={`/errata/?book=${encodeURIComponent(detail.bookTitle)}`}>
-                    <RawHTML Tag="span" html={detail.bookTitle} />
-                    {' '}Errata Page
-                </a>.
-            </div>
-        </React.Fragment>
-    );
-}
diff --git a/src/app/pages/errata-detail/detail/detail.tsx b/src/app/pages/errata-detail/detail/detail.tsx
new file mode 100644
index 000000000..31c78a2b7
--- /dev/null
+++ b/src/app/pages/errata-detail/detail/detail.tsx
@@ -0,0 +1,70 @@
+import React from 'react';
+import RawHTML from '~/components/jsx-helpers/raw-html';
+import {
+    useErrataDetail,
+    shouldShowDecisionDetails,
+    Errata,
+    Detail as DetailData
+} from '~/helpers/errata';
+import './detail.scss';
+
+type Pairs = Array<[s: string, i: keyof DetailData]>;
+
+const detailDataPairs: Pairs = [
+    ['Submission ID', 'id'],
+    ['Title', 'bookTitle'],
+    ['Source', 'source'],
+    ['Status', 'status'],
+    ['Error Type', 'errorType'],
+    ['Location', 'location'],
+    ['Description', 'detail'],
+    ['Date Submitted', 'date']
+];
+const decisionDataPairs: Pairs = [['Decision', 'resolutionNotes']];
+
+function LabelValuePairs({detail, pairs}: {detail: DetailData; pairs: Pairs}) {
+    return (
+        <React.Fragment>
+            {pairs.map((pair) => (
+                <div className="label-value-pair" key={pair[0]}>
+                    <div className="label">{pair[0]}</div>
+                    <RawHTML className="value" html={detail[pair[1]] ?? ''} />
+                </div>
+            ))}
+        </React.Fragment>
+    );
+}
+
+export default function Detail({data}: {data: Errata}) {
+    const detail = useErrataDetail(data);
+
+    if (!detail) {
+        return null;
+    }
+    const showDecisionDetails = shouldShowDecisionDetails(data);
+
+    return (
+        <React.Fragment>
+            {showDecisionDetails && (
+                <div className="info body-block graybottom">
+                    <LabelValuePairs
+                        detail={detail}
+                        pairs={decisionDataPairs}
+                    />
+                </div>
+            )}
+            <div className="info body-block">
+                <LabelValuePairs detail={detail} pairs={detailDataPairs} />
+            </div>
+            <div className="note">
+                {'You can check the status of all errata submissions on the '}
+                <a
+                    href={`/errata/?book=${encodeURIComponent(detail.bookTitle)}`}
+                >
+                    <RawHTML Tag="span" html={detail.bookTitle} /> Errata Page
+                </a>
+                .
+            </div>
+        </React.Fragment>
+    );
+}
diff --git a/src/app/pages/errata-detail/errata-detail.js b/src/app/pages/errata-detail/errata-detail.tsx
similarity index 64%
rename from src/app/pages/errata-detail/errata-detail.js
rename to src/app/pages/errata-detail/errata-detail.tsx
index 46aa1f1dc..169094f09 100644
--- a/src/app/pages/errata-detail/errata-detail.js
+++ b/src/app/pages/errata-detail/errata-detail.tsx
@@ -2,10 +2,11 @@ import LoaderPage from '~/components/jsx-helpers/loader-page';
 import React from 'react';
 import ProgressBar from './progress-bar/progress-bar';
 import Detail from './detail/detail';
-import {getDisplayStatus} from '~/helpers/errata';
+import {getDisplayStatus, Errata} from '~/helpers/errata';
+import {useLocation} from 'react-router-dom';
 import './errata-detail.scss';
 
-function ProgressBarBlock({data}) {
+function ProgressBarBlock({data}: {data: Errata}) {
     const {status, barStatus} = getDisplayStatus(data);
 
     return (
@@ -15,7 +16,7 @@ function ProgressBarBlock({data}) {
     );
 }
 
-export function ErrataDetailBlock({data}) {
+export function ErrataDetailBlock({data}: {data: Errata}) {
     return (
         <div className="errata-detail-block">
             <Detail data={data} />
@@ -23,13 +24,12 @@ export function ErrataDetailBlock({data}) {
     );
 }
 
-function ErrataDetail({data}) {
-    if (!data) {
-        return null;
-    }
+function ErrataDetail({data}: {data: Errata}) {
     return (
         <React.Fragment>
-            <div className="hero padded"><h1>Errata Submission Details</h1></div>
+            <div className="hero padded">
+                <h1>Errata Submission Details</h1>
+            </div>
             <div className="boxed">
                 <ProgressBarBlock data={data} />
                 <ErrataDetailBlock data={data} />
@@ -39,9 +39,11 @@ function ErrataDetail({data}) {
 }
 
 export default function ErrataDetailLoader() {
+    const slug = useLocation().pathname.substring(1);
+
     return (
         <div className="errata-detail page">
-            <LoaderPage slug={window.location.pathname.substring(1)} Child={ErrataDetail} doDocumentSetup />
+            <LoaderPage slug={slug} Child={ErrataDetail} doDocumentSetup />
         </div>
     );
 }
diff --git a/src/app/pages/errata-detail/progress-bar/progress-bar.js b/src/app/pages/errata-detail/progress-bar/progress-bar.tsx
similarity index 79%
rename from src/app/pages/errata-detail/progress-bar/progress-bar.js
rename to src/app/pages/errata-detail/progress-bar/progress-bar.tsx
index 4ffe18299..1a5599edc 100644
--- a/src/app/pages/errata-detail/progress-bar/progress-bar.js
+++ b/src/app/pages/errata-detail/progress-bar/progress-bar.tsx
@@ -2,14 +2,23 @@ import React from 'react';
 import './progress-bar.scss';
 
 // eslint-disable-next-line complexity
-export default function ProgressBar({status, barStatus}) {
-    const thirdNodeFill = ['Corrected', 'Will correct'].includes(barStatus) ?
-        ' filled' : ' filled-no';
-    const bars = barStatus ? 2 : {
-        'In Review': 0,
-        'Reviewed': 1,
-        'Will Correct': 1
-    }[status];
+export default function ProgressBar({
+    status,
+    barStatus
+}: {
+    status: string;
+    barStatus: string;
+}) {
+    const thirdNodeFill = ['Corrected', 'Will correct'].includes(barStatus)
+        ? ' filled'
+        : ' filled-no';
+    const bars = barStatus
+        ? 2
+        : ({
+              'In Review': 0,
+              Reviewed: 1,
+              'Will Correct': 1
+          }[status] as number);
     const firstNodeClass = bars === 0 ? ' filled ' : '';
     const secondNodeClass = bars === 1 ? ' filled' : '';
     const thirdNodeClass = bars > 1 ? thirdNodeFill : '';
diff --git a/test/src/pages/errata/errata-detail.test.tsx b/test/src/pages/errata/errata-detail.test.tsx
new file mode 100644
index 000000000..13790d6fc
--- /dev/null
+++ b/test/src/pages/errata/errata-detail.test.tsx
@@ -0,0 +1,66 @@
+import React from 'react';
+import {render, screen} from '@testing-library/preact';
+import ErrataDetailLoader from '~/pages/errata-detail/errata-detail';
+import MemoryRouter from '~/../../test/helpers/future-memory-router';
+import ProgressBar from '~/pages/errata-detail/progress-bar/progress-bar';
+import * as HE from '~/helpers/errata';
+import * as DH from '~/helpers/use-document-head';
+
+jest.spyOn(DH, 'setPageTitleAndDescriptionFromBookData').mockReturnValue();
+
+describe('Errata Detail', () => {
+    it('renders', async () => {
+        render(
+            <MemoryRouter initialEntries={['/errata/7199']}>
+                <ErrataDetailLoader />
+            </MemoryRouter>
+        );
+        await screen.findByRole('heading', {
+            level: 1,
+            name: 'Errata Submission Details'
+        });
+        await screen.findByText('You can check', {exact: false});
+    });
+    it('renders decision details', async () => {
+        const spySSED = jest
+            .spyOn(HE, 'shouldShowDecisionDetails')
+            .mockReturnValueOnce(true);
+
+        render(
+            <MemoryRouter initialEntries={['/errata/7199']}>
+                <ErrataDetailLoader />
+            </MemoryRouter>
+        );
+        await screen.findByText('You can check', {exact: false});
+        const bb = document.querySelector('.body-block.graybottom');
+
+        expect(bb?.textContent).toBe('Decision');
+        spySSED.mockReset();
+    });
+    describe('progress bar', () => {
+        it('represents reviewed', () => {
+            render(<ProgressBar status="Reviewed" barStatus="" />);
+            const bar = document.querySelectorAll('.progress-bar-layer')[1];
+
+            expect(bar?.innerHTML).toBe(
+                '<div class="node"></div><div class="node filled"></div><div class="node"></div>'
+            );
+        });
+        it('represents will-correct', () => {
+            render(<ProgressBar status="Will Correct" barStatus="" />);
+            const bar = document.querySelectorAll('.progress-bar-layer')[1];
+
+            expect(bar?.innerHTML).toBe(
+                '<div class="node"></div><div class="node filled"></div><div class="node"></div>'
+            );
+        });
+        it('represents corrected', () => {
+            render(<ProgressBar status="anything" barStatus="Corrected" />);
+            const bar = document.querySelectorAll('.progress-bar-layer')[1];
+
+            expect(bar?.innerHTML).toBe(
+                '<div class="node"></div><div class="node"></div><div class="node filled"></div>'
+            );
+        });
+    });
+});