Cache persistence doesn't work

[Enelar]

Initially I thought this is my configuration issue, but then I found this topic: https://community.cloudflare.com/t/testing-workers-with-the-cache-api/181346

However solution from that discussion wont help me. My caching results already had caching reply status. I've noticed that sometimes the caching behavior is unexpected to me, and decided to write tests to address that issue. However, it seems that even with correct wrangler.toml, cache wont be persistent if miniflare was created as part of a jest test.

It seems that between tests the cache being reset, and I don't see any files created in my selected cache folder. I have 500 lines worker with complicated caching logic, and I would like to have tests cover all the corner cases.

https://github.com/cloudflare/miniflare/blob/master/packages/shared-test-environment/src/storage.ts#L43

module.exports = {
    presets: [
        ['@babel/preset-env', {targets: {node: 'current'}}],
        '@babel/preset-typescript',
    ],
};

export default {
  testEnvironment: "miniflare",
  // Configuration is automatically loaded from `.env`, `package.json` and
  // `wrangler.toml` files by default, but you can pass any additional Miniflare
  // API options here:
  testEnvironmentOptions: {
    bindings: { KEY: "value" },
    kvNamespaces: ["TEST_NAMESPACE"],
  },
};

name = "cloudflare-proxy"
main = "src/index.ts"
compatibility_date = "2022-12-30"
send_metrics = false

[miniflare]
cache_persist = "./cache/"

[Enelar]

I've managed to overcome this limitation using nasty hack, but this is a clearly not the best workaround.
I'm exposing reference #storage field and moving it across instances, but I would love to see this fixed.
https://github.com/cloudflare/miniflare/blob/master/packages/cache/src/cache.ts#L184

  afterEach(() => {
    cache_persist = caches.default.hack_storage.map;
  })
  beforeEach(() => {
    caches.default.hack_storage.map = cache_persist;
  })

On a side not I would love to see more time-manipulation available for tests. What happens when cache just expired, etc. I would like to include that into integration tests.

[mrbbot]

Hey! 👋 Happy new year! Just catching up with issues now. 🙂

When using the "miniflare" testEnvironment for Jest, all storage operations performed in a test are intentionally undone at the end. This means updates from one test aren't visible in another, and tests can be reordered. See https://miniflare.dev/testing/jest#isolated-storage for more details. If you're trying to seed data for your tests, you should do so in beforeAll/beforeEach hooks. I might be misunderstanding what you're trying to do here though.

On a side not I would love to see more time-manipulation available for tests.

With the Miniflare Jest environment, you should be able to use Jest's standard timer mocks (https://jestjs.io/docs/timer-mocks), specifically with https://jestjs.io/docs/jest-object#jestsetsystemtimenow-number--date to test cache expiry.

[admah]

@Enelar I'm going to close this out due to inactivity. If the explanation from @mrbbot doesn't solve the issue, feel free to reopen.

[Enelar]

@mrbbot, I see the logic behind it. However this is somewhat unexpected. When I create an instance of some object, and use in my test I won't expect it to have same fancy logic around tests. Could you please add this into documentation?

Also, there is no way to save-restore cache state, which bloats tests.