diff --git a/packages/components/psammead-story-promo/src/layout.test.jsx b/packages/components/psammead-story-promo/src/layout.test.jsx
new file mode 100644
index 000000000..19d67112d
--- /dev/null
+++ b/packages/components/psammead-story-promo/src/layout.test.jsx
@@ -0,0 +1,218 @@
+import React from 'react';
+import { render } from '@testing-library/react';
+import { latin } from '@bbc/gel-foundations/scripts';
+import StoryPromo, { Headline, Summary, Link } from './index';
+
+const Image = <img src="https://foobar.com/image.png" alt="Alt text" />;
+
+const Info = ({ promoType }) => (
+  <>
+    <Headline script={latin} promoType={promoType} service="news">
+      <Link href="https://www.bbc.co.uk/news">The headline</Link>
+    </Headline>
+    <Summary script={latin} promoType={promoType} service="news">
+      The summary
+    </Summary>
+    <time>12 March 2019</time>
+  </>
+);
+
+const renderLeading = () => {
+  const { container } = render(
+    <StoryPromo
+      image={Image}
+      info={<Info promoType="leading" />}
+      promoType="leading"
+    />,
+  );
+  return container;
+};
+
+const getCss = () =>
+  Array.from(document.querySelectorAll('style'))
+    .map(s => s.textContent || '')
+    .join('\n');
+
+const hashClass = el => {
+  const classes = (el.getAttribute('class') || '').split(/\s+/).filter(Boolean);
+
+  return classes.filter(c => !c.includes('-sc-'))[0] || classes[classes.length - 1];
+};
+
+const escRe = s => s.replace(/[.()/\\+*?^$|[\]{}]/g, m => `\\${m}`);
+
+
+
+
+
+const matchInMedia = (css, cls, minWidth, needle) => {
+  const pattern = new RegExp(
+    `@media\\s*\\(min-width:\\s*${escRe(
+      minWidth,
+    )}\\)(?:\\s*and\\s*\\(max-width:[^)]+\\))?\\s*\\{[^}]*\\.${cls}\\s*\\{[^}]*${escRe(
+      needle,
+    )}`,
+  );
+  return pattern.test(css);
+};
+
+
+
+
+const hasGridColumn1Span = (css, cls, minWidth, n) => {
+  const blockPattern = new RegExp(
+    `@media\\s*\\(min-width:\\s*${escRe(
+      minWidth,
+    )}\\)(?:\\s*and\\s*\\(max-width:[^)]+\\))?\\s*\\{([^}]*\\.${cls}\\s*\\{[^}]*\\})`,
+    'g',
+  );
+  const bad = new RegExp(
+    `\\.${cls}\\s*\\{[^}]*grid-column:\\s*1\\s*/\\s*span\\s+${n}\\b`,
+  );
+  let m;
+  // eslint-disable-next-line no-cond-assign
+  while ((m = blockPattern.exec(css))) {
+    if (bad.test(m[1])) return true;
+  }
+  return false;
+};
+
+describe('StoryPromo - Leading layout', () => {
+  it('renders TextGridItem (info) before ImageGridItem (image) in DOM order', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    expect(wrapper.children).toHaveLength(2);
+    const first = wrapper.children[0];
+    const second = wrapper.children[1];
+
+    expect(first.querySelector('h3')).not.toBeNull();
+    expect(first.querySelector('img')).toBeNull();
+    expect(second.querySelector('img')).not.toBeNull();
+    expect(second.querySelector('h3')).toBeNull();
+  });
+
+  it('uses 6/6 grid columns at default (mobile, < 600px) for both items', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const textCls = hashClass(wrapper.children[0]);
+    const imageCls = hashClass(wrapper.children[1]);
+    const css = getCss();
+
+
+
+
+
+
+    expect(css).toMatch(new RegExp(`\\.${textCls}\\s*\\{[^}]*span\\s+6\\b`));
+    expect(css).toMatch(new RegExp(`\\.${imageCls}\\s*\\{[^}]*span\\s+6\\b`));
+  });
+
+  it('uses 3/3 grid columns at min-width 37.5rem (600px) for both items', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const textCls = hashClass(wrapper.children[0]);
+    const imageCls = hashClass(wrapper.children[1]);
+    const css = getCss();
+
+    expect(matchInMedia(css, textCls, '37.5rem', 'span 3')).toBe(true);
+    expect(matchInMedia(css, imageCls, '37.5rem', 'span 3')).toBe(true);
+
+
+
+
+
+    expect(hasGridColumn1Span(css, imageCls, '37.5rem', 3)).toBe(false);
+  });
+
+  it('uses 2/4 grid columns at min-width 63rem (1008px)', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const textCls = hashClass(wrapper.children[0]);
+    const imageCls = hashClass(wrapper.children[1]);
+    const css = getCss();
+
+
+    expect(matchInMedia(css, textCls, '63rem', 'span 2')).toBe(true);
+
+    expect(matchInMedia(css, imageCls, '63rem', 'span 4')).toBe(true);
+
+
+
+    expect(hasGridColumn1Span(css, imageCls, '63rem', 4)).toBe(false);
+  });
+
+  it('TextGridItem fallback width is 100% by default (no @supports)', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const textCls = hashClass(wrapper.children[0]);
+    const css = getCss();
+
+
+    expect(css).toMatch(
+      new RegExp(`\\.${textCls}\\s*\\{[^}]*width:\\s*100%`),
+    );
+  });
+
+  it('TextGridItem fallback width is 50% at min-width 37.5rem', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const textCls = hashClass(wrapper.children[0]);
+    const css = getCss();
+
+    expect(matchInMedia(css, textCls, '37.5rem', 'width:50%')).toBe(true);
+  });
+
+  it('TextGridItem fallback width is 33.33% at min-width 63rem', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const textCls = hashClass(wrapper.children[0]);
+    const css = getCss();
+
+    expect(matchInMedia(css, textCls, '63rem', 'width:33.33%')).toBe(true);
+  });
+
+  it('ImageGridItem fallback width is 100% by default', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const imageCls = hashClass(wrapper.children[1]);
+    const css = getCss();
+
+    expect(css).toMatch(
+      new RegExp(`\\.${imageCls}\\s*\\{[^}]*width:\\s*100%`),
+    );
+  });
+
+  it('ImageGridItem fallback width is 50% at min-width 37.5rem', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const imageCls = hashClass(wrapper.children[1]);
+    const css = getCss();
+
+    expect(matchInMedia(css, imageCls, '37.5rem', 'width:50%')).toBe(true);
+  });
+
+  it('ImageGridItem fallback width is 66.67% at min-width 63rem', () => {
+    const container = renderLeading();
+    const wrapper = container.firstChild;
+    const imageCls = hashClass(wrapper.children[1]);
+    const css = getCss();
+
+    expect(matchInMedia(css, imageCls, '63rem', 'width:66.67%')).toBe(true);
+  });
+});
+
+describe('StoryPromo - Regular promo unaffected', () => {
+  it('regular promo still renders image before info', () => {
+    const { container } = render(
+      <StoryPromo
+        image={Image}
+        info={<Info promoType="regular" />}
+        promoType="regular"
+      />,
+    );
+    const wrapper = container.firstChild;
+    expect(wrapper.children).toHaveLength(2);
+    expect(wrapper.children[0].querySelector('img')).not.toBeNull();
+    expect(wrapper.children[1].querySelector('h3')).not.toBeNull();
+  });
+});
diff --git a/test_commands.json b/test_commands.json
new file mode 100644
index 000000000..9d666d9bf
--- /dev/null
+++ b/test_commands.json
@@ -0,0 +1,3 @@
+{
+  "test_commands": ["npx jest packages/components/psammead-story-promo/src/layout.test.jsx --colors=false"]
+}
diff --git a/mimo_test_command.sh b/mimo_test_command.sh
new file mode 100755
--- /dev/null
+++ b/mimo_test_command.sh
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+set -uo pipefail
+cd /testbed
+rc=0
+npx jest packages/components/psammead-story-promo/src/layout.test.jsx --colors=false
+rc=$(( rc | $? ))
+exit $rc