more btrfs unit tests

Author: williamstein

src/packages/file-server/btrfs/subvolume.ts

@@ -219,7 +219,11 @@ export class Subvolume {
     const s = await this.snapshots();
     if (s.length == 0) {
       // more than just the SNAPSHOTS directory?
-      return (await listdir(this.path)).length > 1;
+      const v = await listdir(this.path);
+      if (v.length == 0 || (v.length == 1 && v[0] == this.snapshotsDir)) {
+        return false;
+      }
+      return true;
     }
     const pathGen = await getGeneration(this.path);
     const snapGen = await getGeneration(

src/packages/file-server/btrfs/test/setup.ts

@@ -7,6 +7,8 @@ import { chmod, mkdtemp, mkdir, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "path";
 import { until } from "@cocalc/util/async-utils";
+export { sudo } from "../util";
+export { delay } from "awaiting";
 
 export let fs: Filesystem;
 let tempDir;

src/packages/file-server/btrfs/test/subvolume.test.ts

@@ -1,7 +1,6 @@
-import { before, after, fs } from "./setup";
-import { writeFile } from "fs/promises";
+import { before, after, fs, sudo } from "./setup";
+import { readFile, writeFile, unlink } from "fs/promises";
 import { join } from "path";
-import { delay } from "awaiting";
 import { wait } from "@cocalc/backend/conat/test/util";
 import { randomBytes } from "crypto";
 
@@ -24,7 +23,7 @@ describe("setting and getting quota of a subvolume", () => {
     await writeFile(join(vol.path, "buf"), buf);
     await wait({
       until: async () => {
-        await delay(1000);
+        await sudo({ command: "sync" });
         const { used } = await vol.usage();
         return used > 0;
       },
@@ -42,4 +41,54 @@ describe("setting and getting quota of a subvolume", () => {
   });
 });
 
+describe("test snapshots", () => {
+  let vol;
+  it("creates a volume and write a file to it", async () => {
+    vol = await fs.subvolume("snapper");
+    expect(await vol.hasUnsavedChanges()).toBe(false);
+    await writeFile(join(vol.path, "a.txt"), "hello");
+    expect(await vol.hasUnsavedChanges()).toBe(true);
+  });
+
+  it("snapshot the volume", async () => {
+    expect(await vol.snapshots()).toEqual([]);
+    await vol.createSnapshot("snap1");
+    expect(await vol.snapshots()).toEqual(["snap1"]);
+    expect(await vol.hasUnsavedChanges()).toBe(false);
+  });
+
+  it("create a file see that we know there are unsaved changes", async () => {
+    await writeFile(join(vol.path, "b.txt"), "world");
+    await sudo({ command: "sync" });
+    expect(await vol.hasUnsavedChanges()).toBe(true);
+  });
+
+  it("delete our file, but then read it in a snapshot", async () => {
+    await unlink(join(vol.path, "a.txt"));
+    const b = await readFile(join(vol.snapshotsDir, "snap1", "a.txt"), "utf8");
+    expect(b).toEqual("hello");
+  });
+
+  it("verifies snapshot exists", async () => {
+    expect(await vol.snapshotExists("snap1")).toBe(true);
+    expect(await vol.snapshotExists("snap2")).toBe(false);
+  });
+
+  it("lock our snapshot and confirm it prevents deletion", async () => {
+    await vol.lockSnapshot("snap1");
+    expect(async () => {
+      await vol.deleteSnapshot("snap1");
+    }).rejects.toThrow("locked");
+  });
+
+  it("unlock our snapshot and delete it", async () => {
+    await vol.unlockSnapshot("snap1");
+    await vol.deleteSnapshot("snap1");
+    expect(await vol.snapshotExists("snap1")).toBe(false);
+    expect(await vol.snapshots()).toEqual([]);
+  });
+
+
+});
+
 afterAll(after);