ENH - use Inter across phone UI

frontend/src/ui/InterFont.contract.test.ts

@@ -0,0 +1,59 @@
+import { existsSync, readdirSync, readFileSync } from 'node:fs'
+import { join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+import { describe, expect, it } from 'vitest'
+
+const sourceDirectory = fileURLToPath(new URL('..', import.meta.url))
+const tokensSource = readFileSync(new URL('./tokens.css', import.meta.url), 'utf8')
+const mainCssSource = readFileSync(
+  new URL('../assets/main.css', import.meta.url),
+  'utf8',
+)
+
+function styleSources(directory: string): Array<{
+  file: string
+  source: string
+}> {
+  return readdirSync(directory, { withFileTypes: true }).flatMap((entry) => {
+    const path = join(directory, entry.name)
+    if (entry.isDirectory()) return styleSources(path)
+    if (!/\.(?:css|vue)$/.test(entry.name)) return []
+    return [{ file: path, source: readFileSync(path, 'utf8') }]
+  })
+}
+
+describe('Inter font contract', () => {
+  it('bundles normal and italic variable fonts for every supported weight', () => {
+    expect(
+      existsSync(new URL('../assets/fonts/InterVariable.woff2', import.meta.url)),
+    ).toBe(true)
+    expect(
+      existsSync(
+        new URL('../assets/fonts/InterVariable-Italic.woff2', import.meta.url),
+      ),
+    ).toBe(true)
+    expect(tokensSource.match(/@font-face/g)).toHaveLength(2)
+    expect(tokensSource.match(/font-weight:\s*100 900;/g)).toHaveLength(2)
+    expect(tokensSource).toContain("--sky-font-family: 'Inter', Arial, sans-serif;")
+  })
+
+  it('applies the shared font to the document and native form controls', () => {
+    expect(mainCssSource).toMatch(
+      /:root\s*\{[\s\S]*?font-family:\s*var\(--sky-font-family\);/,
+    )
+    expect(mainCssSource).toMatch(
+      /button,\s*input,\s*textarea,\s*select\s*\{\s*font:\s*inherit;/,
+    )
+  })
+
+  it('does not bypass the shared token with a generic system UI stack', () => {
+    const genericSystemStack =
+      /font-family\s*:\s*(?:-apple-system|BlinkMacSystemFont|system-ui|ui-sans-serif|['"]Segoe UI['"])/
+    const violations = styleSources(sourceDirectory)
+      .filter(({ source }) => genericSystemStack.test(source))
+      .map(({ file }) => file.slice(sourceDirectory.length + 1))
+
+    expect(violations).toEqual([])
+  })
+})