expect((await fs.stat(filePath)).isFile()).toBe(true);

}

async function expectPathMissing(filePath: string): Promise<void> {

await expect(fs.stat(filePath)).rejects.toMatchObject({ code: "ENOENT" });

}

describe("config backup rotation", () => {

it("keeps a 5-deep backup ring for config writes", async () => {

await withTempHome(async () => {

await expect(readName(".bak.2")).resolves.toBe("v3");

await expect(readName(".bak.3")).resolves.toBe("v2");

await expect(readName(".bak.4")).resolves.toBe("v1");

await expect(fs.stat(`${configPath}.bak.5`)).rejects.toThrow();

await expectPathMissing(`${configPath}.bak.5`);

});

});

await expectRegularFile(`${configPath}.bak.2`);

// Orphans removed

await expect(fs.stat(`${configPath}.bak.1772352289`)).rejects.toThrow();

await expect(fs.stat(`${configPath}.bak.before-marketing`)).rejects.toThrow();

await expect(fs.stat(`${configPath}.bak.99`)).rejects.toThrow();

await expectPathMissing(`${configPath}.bak.1772352289`);

await expectPathMissing(`${configPath}.bak.before-marketing`);

await expectPathMissing(`${configPath}.bak.99`);

// Main config untouched

await expect(fs.readFile(configPath, "utf-8")).resolves.toBe("current");

expectPosixMode(primaryBackupStat.mode, 0o600);

}

// Out-of-ring orphan gets pruned.

await expect(fs.stat(`${configPath}.bak.orphan`)).rejects.toThrow();

await expectPathMissing(`${configPath}.bak.orphan`);

});

});

});