Add test for commonmark spec (#18428)

scripts/clean-markdown-legacy-spec.js

@@ -0,0 +1,19 @@
+import fs from "node:fs/promises";
+import { commonmark } from "commonmark.json";
+
+const existing = new Set(commonmark.map(({ markdown }) => markdown.trim()));
+const DIRECTORY = new URL(
+  "../tests/format/markdown/legacy-spec/",
+  import.meta.url,
+);
+
+for (const file of await fs.readdir(DIRECTORY, { withFileTypes: true })) {
+  if (!file.isFile()) {
+    continue;
+  }
+  const fileUrl = new URL(file.name, DIRECTORY);
+  const content = await fs.readFile(fileUrl, "utf8");
+  if (existing.has(content.trim())) {
+    await fs.rm(new URL(file.name, DIRECTORY));
+  }
+}

scripts/format-test-lint.js

@@ -10,7 +10,7 @@ const FORMAT_TEST_DIRECTORY = path.join(PROJECT_ROOT, "tests/format/");
 const TEST_SCRIPT_FILE_NAME = "format.test.js";
 const SNAPSHOTS_DIRECTORY_NAME = "__snapshots__";
 const IGNORED = new Set([
-  path.join(FORMAT_TEST_DIRECTORY, "markdown/spec/remark-bug"),
+  path.join(FORMAT_TEST_DIRECTORY, "markdown/spec-legacy/remark-bug"),
 ]);
 
 async function* checkDirectory(directory) {