publish(task 17): validate-post-subcommand

validatePostFile(path) liest post-datei, parst frontmatter, ruft
validatePost aus core/validation. liefert { ok, slug?, error? }.
offline-befehl ohne netz-zugriff. 3 tests grün.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

publish/src/subcommands/validate-post.ts

@@ -0,0 +1,24 @@
+import { parseFrontmatter } from '../core/frontmatter.ts'
+import { validatePost } from '../core/validation.ts'
+
+export interface ValidateResult {
+  ok: boolean
+  slug?: string
+  error?: string
+}
+
+export async function validatePostFile(path: string): Promise<ValidateResult> {
+  let text: string
+  try {
+    text = await Deno.readTextFile(path)
+  } catch (err) {
+    return { ok: false, error: `cannot read ${path}: ${err instanceof Error ? err.message : err}` }
+  }
+  try {
+    const { fm } = parseFrontmatter(text)
+    validatePost(fm)
+    return { ok: true, slug: fm.slug }
+  } catch (err) {
+    return { ok: false, error: err instanceof Error ? err.message : String(err) }
+  }
+}

publish/tests/validate-post_test.ts

@@ -0,0 +1,29 @@
+import { assertEquals } from '@std/assert'
+import { validatePostFile } from '../src/subcommands/validate-post.ts'
+
+Deno.test('validatePostFile: ok bei fixture-post', async () => {
+  const result = await validatePostFile('./tests/fixtures/sample-post.md')
+  assertEquals(result.ok, true)
+  assertEquals(result.slug, 'sample-slug')
+})
+
+Deno.test('validatePostFile: fehler bei fehlender datei', async () => {
+  const result = await validatePostFile('./does-not-exist.md')
+  assertEquals(result.ok, false)
+  assertEquals(result.error?.includes('read'), true)
+})
+
+Deno.test('validatePostFile: fehler bei ungültigem slug', async () => {
+  const tmp = await Deno.makeTempFile({ suffix: '.md' })
+  try {
+    await Deno.writeTextFile(
+      tmp,
+      '---\ntitle: "T"\nslug: "Bad Slug"\ndate: 2024-01-01\n---\n\nbody',
+    )
+    const result = await validatePostFile(tmp)
+    assertEquals(result.ok, false)
+    assertEquals(result.error?.includes('slug'), true)
+  } finally {
+    await Deno.remove(tmp)
+  }
+})