blob: 826b4a00d0b433575c662a6b8b23a42a40773763 [file] [log] [blame]
// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//! This file demonstrates how one can use the `fuchsia.sys.test.CacheControl` protocol to test
//! code that uses the `isolated-cache-storage` feature to store data on disk. This file doubles as
//! an integration test for appmgr, as the example and test are identical. Take care when changing
//! this file to not accidentally reduce test coverage of appmgr.
use std::{fs, io};
const FILE_PATH: &str = "/cache/example_file";
const FILE_CONTENTS: &str = "I was stored in isolated cache storage!";
fn main() {
println!("file contents: \"{}\"", get_contents_of_cache_file());
// get_contents_of_cache_file will attempt to read `FILE_PATH` from the filesystem. If the file
// doesn't exist, it will create it and then read it. This function aims to mimic use cases for
// isolated cache storage, wherein files are stored on disk that can be recreated if deleted.
fn get_contents_of_cache_file() -> String {
let res = fs::read_to_string(FILE_PATH);
match res {
Ok(msg) => msg,
Err(e) => {
if e.kind() != io::ErrorKind::NotFound {
panic!("failed to read file '{}': {:?}", FILE_PATH, e);
fs::write(FILE_PATH, FILE_CONTENTS).expect("failed to write file");
fs::read_to_string(FILE_PATH).expect("failed to read file")
mod tests {
use {
anyhow::{Context, Error},
fidl_fuchsia_sys_test as systest,
std::path::{Path, PathBuf},
fn read_dir_paths<P: AsRef<Path>>(dir: P) -> Result<Vec<PathBuf>, io::Error> {
fs::read_dir(dir)?.map(|r||d| d.path())).collect()
async fn my_test() -> Result<(), Error> {
// Populate the contents of the cache file, and make sure we can read it
assert_eq!(FILE_CONTENTS, get_contents_of_cache_file());
// A second call to this function should have the same behavior
assert_eq!(FILE_CONTENTS, get_contents_of_cache_file());
// Make sure the contents of /cache match what we expect
assert_eq!(vec![PathBuf::from(FILE_PATH)], read_dir_paths("/cache")?);
// Connect to CacheControl, clear the cache for the system
let cache_control = connect_to_protocol::<systest::CacheControlMarker>()?;
cache_control.clear().await.context("failed to clear cache")?;
// Make sure the contents of /cache match what we expect
// This function should still succeed, and will repopulate the cache file
assert_eq!(FILE_CONTENTS, get_contents_of_cache_file());
// Make sure the contents of /cache were repopulated
assert_eq!(vec![PathBuf::from(FILE_PATH)], read_dir_paths("/cache")?);