remember-this 0.1.0

extern crate env_logger;

use remember_this::*;
use std::sync::atomic::Ordering;

/// Test that we can fill the cache and recover data
#[tokio::test]
async fn test_simple() {
    let _ = env_logger::builder().is_test(true).try_init();
    let manager = CacheManager::new(
        &CacheManagerOptions::builder()
            .path("/tmp/test_simple.db")
            .use_temporary(true)
            .build(),
    )
    .unwrap();
    let cache = manager
        .cache("cache_1", &CacheOptions::builder().purge(true).build())
        .unwrap();

    // Cache is initially empty.
    for i in 0..100 {
        let obtained = cache.get(&i).unwrap();
        assert!(obtained.is_none(), "Cache should initially be empty");
    }

    // Fill the cache.
    for i in 0..100 {
        let was_evaluated = std::sync::atomic::AtomicBool::new(false);
        let obtained = cache
            .get_or_insert_infallible(&i, async {
                let _ = was_evaluated.store(true, Ordering::SeqCst);
                i * i
            })
            .await
            .unwrap();
        assert_eq!(
            *obtained,
            i * i,
            "The cache should return the right value when it's evaluating."
        );
        assert_eq!(
            was_evaluated.load(Ordering::SeqCst),
            true,
            "The cache should be evaluating when there is no data."
        );
    }

    // Now run again with cache filled.
    for _ in 0..3 {
        for i in 0..100 {
            let was_evaluated = std::sync::atomic::AtomicBool::new(false);
            let obtained = cache
                .get_or_insert_infallible(&i, async {
                    let _ = was_evaluated.store(true, Ordering::SeqCst);
                    i * i
                })
                .await
                .unwrap();
            assert_eq!(
                *obtained,
                i * i,
                "The cache should return the right value when it's not evaluating."
            );
            assert_eq!(
                was_evaluated.load(Ordering::SeqCst),
                false,
                "The cache should not be evaluating when there is data already."
            );

            assert_eq!(cache.get(&i).unwrap().unwrap(), obtained);
        }
    }
}

/// Test that we erase data silently in case of format change.
#[tokio::test]
async fn test_format_change() {
    let _ = env_logger::builder().is_test(true).try_init();
    let manager = CacheManager::new(
        &CacheManagerOptions::builder()
            .path("/tmp/test_format_change.db")
            .use_temporary(true)
            .build(),
    )
    .unwrap();

    {
        // Open the cache as `<i32, i32>`.
        let cache = manager
            .cache("cache_2", &CacheOptions::builder().purge(true).build())
            .unwrap();

        // Fill the cache.
        for i in 0..100 {
            cache
                .get_or_insert_infallible(&i, async { i * i })
                .await
                .unwrap();
        }
    }

    {
        // Reopen the cache as `<i32, String>`
        let cache = manager
            .cache("cache_2", &CacheOptions::builder().purge(true).build())
            .unwrap();

        // Re-access data
        for i in 0..100 {
            let was_evaluated = std::sync::atomic::AtomicBool::new(false);
            let found = cache
                .get_or_insert_infallible(&i, async {
                    was_evaluated.store(true, Ordering::SeqCst);
                    format!("{}", i * i)
                })
                .await
                .unwrap();
            assert_eq!(
                *found,
                format!("{}", i * i),
                "When silently overwriting because of format change, we get the right result"
            );
            assert_eq!(
                was_evaluated.load(Ordering::SeqCst),
                true,
                "When silently overwriting because of format change, we executed the thunk"
            );
        }
    }

    {
        // Reopen the cache as `<String, bool>`
        let cache = manager
            .cache("cache_2", &CacheOptions::builder().purge(true).build())
            .unwrap();

        // Fill the cache.
        for i in 0..100 {
            let was_evaluated = std::sync::atomic::AtomicBool::new(false);
            let found = cache
                .get_or_insert_infallible(&i, async {
                    was_evaluated.store(true, Ordering::SeqCst);
                    i % 2 == 0
                })
                .await
                .unwrap();
            assert_eq!(
                *found,
                i % 2 == 0,
                "When silently overwriting because of format change, we get the right result"
            );
            assert_eq!(
                was_evaluated.load(Ordering::SeqCst),
                true,
                "When silently overwriting because of format change, we executed the thunk"
            );
        }
    }
}

/// Test that we can reload by reopening the cache.
#[tokio::test]
async fn test_reopen() {
    let _ = env_logger::builder().is_test(true).try_init();
    let manager = CacheManager::new(
        &CacheManagerOptions::builder()
            .path("/tmp/test_reopen.db")
            .use_temporary(true)
            .build(),
    )
    .unwrap();

    async fn walk_through_cache(
        manager: &CacheManager,
        options: &CacheOptions,
        should_execute: bool,
        subtest: &str,
    ) {
        eprintln!("Starting test {}", subtest);
        let cache = manager.cache("cache_1", &options).unwrap();

        // Fill the cache.
        for i in 0..100 {
            eprintln!("{}:{}", subtest, i);
            let was_evaluated = std::sync::atomic::AtomicBool::new(false);
            let obtained = cache
                .get_or_insert_infallible(&i, async {
                    let _ = was_evaluated.store(true, Ordering::SeqCst);
                    i * i
                })
                .await
                .unwrap();
            assert_eq!(
                *obtained,
                i * i,
                "The cache should return the right value: {}.",
                subtest
            );
            assert_eq!(
                was_evaluated.load(Ordering::SeqCst),
                should_execute,
                "The cache should be evaluating: {}.",
                subtest
            );
        }
    }

    // Initialize cache.
    walk_through_cache(
        &manager,
        &CacheOptions::builder().purge(true).build(),
        true,
        "initializer",
    )
    .await;
    walk_through_cache(
        &manager,
        &CacheOptions::builder().build(),
        false,
        "simple reopen",
    )
    .await;

    // Purge the cache.
    walk_through_cache(
        &manager,
        &CacheOptions::builder().purge(true).build(),
        true,
        "purge",
    )
    .await;
    walk_through_cache(
        &manager,
        &CacheOptions::builder().build(),
        false,
        "reopen 2",
    )
    .await;

    // Change version number.
    walk_through_cache(
        &manager,
        &CacheOptions::builder().version(1).build(),
        true,
        "change version number",
    )
    .await;
    walk_through_cache(
        &manager,
        &CacheOptions::builder().version(1).build(),
        false,
        "reopen with same new version",
    )
    .await;
}