chore(core): Cover font construction with unit (snapshot) tests

src/core/packages/rendering/server-internal/src/views/fonts.test.tsx

@@ -0,0 +1,101 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import React from 'react';
+import { renderToStaticMarkup } from 'react-dom/server';
+import { load } from 'cheerio';
+
+import { Fonts } from './fonts';
+
+const TEST_URL = '/test-base-path';
+
+const getRenderedCss = () => {
+  const markup = renderToStaticMarkup(<Fonts url={TEST_URL} />);
+  const dom = load(markup);
+
+  return dom('style').html() ?? '';
+};
+
+const getFontFaceBlock = ({
+  family,
+  style,
+  weight,
+}: {
+  family: string;
+  style: 'normal' | 'italic';
+  weight: string | number;
+}) => {
+  const blocks = getRenderedCss().match(/@font-face\s*{[\s\S]*?}/g) ?? [];
+  const block = blocks.find(
+    (candidate) =>
+      candidate.includes(`font-family: '${family}';`) &&
+      candidate.includes(`font-style: ${style};`) &&
+      candidate.includes(`font-weight: ${weight};`)
+  );
+
+  expect(block).toBeDefined();
+
+  return block!;
+};
+
+describe('Fonts', () => {
+  it('renders optional font-face declarations when configured', () => {
+    expect(
+      getFontFaceBlock({
+        family: 'Elastic UI Numeric',
+        style: 'normal',
+        weight: '100 900',
+      })
+    ).toMatchInlineSnapshot(`
+"@font-face {
+          font-family: 'Elastic UI Numeric';
+          font-style: normal;
+          font-weight: 100 900;
+          font-display: swap;
+          src: url('/test-base-path/fonts/elastic_ui_numeric/ElasticUINumeric-Variable.woff2') format('woff2');
+          unicode-range: U+20, U+24-25, U+28-29, U+2B-2F, U+30-3A, U+A0, U+202F, U+2212;
+        }"
+`);
+  });
+
+  it('omits optional font-face declarations when they are not configured', () => {
+    expect(
+      getFontFaceBlock({
+        family: 'Inter',
+        style: 'normal',
+        weight: 100,
+      })
+    ).toMatchInlineSnapshot(`
+"@font-face {
+          font-family: 'Inter';
+          font-style: normal;
+          font-weight: 100;
+          src: url('/test-base-path/fonts/inter/Inter-Thin.woff2') format('woff2');
+        }"
+`);
+  });
+
+  it('renders unicode-range without font-display when only unicode range is configured', () => {
+    expect(
+      getFontFaceBlock({
+        family: 'Roboto Mono',
+        style: 'normal',
+        weight: 400,
+      })
+    ).toMatchInlineSnapshot(`
+"@font-face {
+          font-family: 'Roboto Mono';
+          font-style: normal;
+          font-weight: 400;
+          src: local('Roboto Mono'), local('RobotoMono-Regular'), url('/test-base-path/fonts/roboto_mono/RobotoMono-Regular.ttf') format('woff2');
+          unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+        }"
+`);
+  });
+});