Centralise setup tool Commonlib selection

utils/livesync-commonlib-version.test.ts

@@ -0,0 +1,27 @@
+import { LIVESYNC_COMMONLIB_VERSION } from "./livesync-commonlib-version.ts";
+
+function assert(condition: unknown, message: string): asserts condition {
+  if (!condition) throw new Error(message);
+}
+
+Deno.test("standalone utilities select one exact Commonlib registry version", async () => {
+  const facadeURLs = [
+    new URL("./setup/livesync-commonlib.ts", import.meta.url),
+    new URL("./couchdb/livesync-commonlib.ts", import.meta.url),
+  ];
+  const selectedVersions = (
+    await Promise.all(facadeURLs.map((url) => Deno.readTextFile(url)))
+  ).flatMap((source) =>
+    [...source.matchAll(
+      /npm:@vrtmrz\/livesync-commonlib@([^/"]+)\//gu,
+    )].map((match) => match[1])
+  );
+
+  assert(selectedVersions.length > 0, "no Commonlib npm specifier was found");
+  assert(
+    selectedVersions.every((version) => version === LIVESYNC_COMMONLIB_VERSION),
+    `Commonlib specifiers do not all select ${LIVESYNC_COMMONLIB_VERSION}: ${
+      selectedVersions.join(", ")
+    }`,
+  );
+});