Add basic roundtrip test for changes index

test/changes-index.test.js

@@ -0,0 +1,37 @@
+const test = require('tape');
+const fs = require('fs/promises');
+
+const { writeChangesFile, readChangesFile, mergeChangesFiles } = require('../storage/lake/changes-index');
+
+test('roundtrip', async t => {
+    await roundtrip(t, 'app.nearcrowd.near.dat');
+    await roundtrip(t, 'asset-manager.orderly-network.near.dat');
+    await roundtrip(t, 'changes.dat');
+});
+
+async function roundtrip(t, fileName) {
+    const indexFileName = `test/data/lake/index/${fileName}`;
+    const changes = await readStream(await readChangesFile(indexFileName));
+    const tempFileName = `${indexFileName}.tmp`;
+    await writeChangesFile(tempFileName, convertChanges(changes));
+    const tempChanges = await readStream(await readChangesFile(tempFileName));
+    t.deepEqual(tempChanges, changes);
+    t.ok((await fs.readFile(tempFileName)).equals(await fs.readFile(indexFileName)));
+}
+
+async function readStream(stream) {
+    const chunks = [];
+    for await (const chunk of stream) {
+        chunks.push(chunk);
+    }
+    return chunks;
+}
+
+function convertChanges(allChanges) {
+    const result = {};
+    for (const { accountId, key, changes } of allChanges) {
+        result[accountId] = result[accountId] || [];
+        result[accountId].push({ key, changes });
+    }
+    return result;
+}