Struct InMemoryRepository 

pub struct InMemoryRepository<T: CacheEntity> { /* private fields */ }

Simple in-memory repository for testing cache-kit implementations.

Provides a straightforward mock DataRepository suitable for unit tests where you want to control what data is “stored” without setting up a real database.

Why Use InMemoryRepository

• Fast Tests: No database setup, teardown, or network calls
• Deterministic: Control exactly what data is present
• Isolated: Each test can have its own data without conflicts
• Simple: Easy to understand test behavior and debug failures

Example Usage

#[tokio::test]
async fn test_cache_expander_with_mock_data() {
    // Create and populate mock repository
    let mut repo = InMemoryRepository::new();
    repo.insert("user:1".to_string(), my_user_entity);

    // Use with cache-kit components
    let mut feeder = MyFeeder::new();
    let result = expander.with(&mut feeder, &repo, CacheStrategy::Refresh).await;

    assert!(result.is_ok());
}

Testing Different Scenarios

• Cache hit: Populate repo, cache will find the data
• Cache miss: Keep repo empty, cache will fallback to repo (which has nothing)
• Invalidation: Clear repo between operations to test refresh behavior
• Batch operations: Use fetch_by_ids() to test multi-key scenarios

Implementations

impl<T: CacheEntity> InMemoryRepository<T>

pub fn new() -> Self

Create a new empty in-memory repository.

Example

let repo = InMemoryRepository::<MyEntity>::new();
assert!(repo.is_empty());

pub fn insert(&mut self, id: T::Key, value: T)

Insert or update an entity by key.

Example

repo.insert("user:123".to_string(), my_user);
let found = repo.fetch_by_id(&"user:123".to_string()).await?;

pub fn clear(&mut self)

Remove all entities from the repository.

Useful for resetting state between test cases.

Example

repo.insert("user:1".to_string(), entity);
assert_eq!(repo.len(), 1);
repo.clear();
assert!(repo.is_empty());

pub fn len(&self) -> usize

Return the number of entities in the repository.

pub fn is_empty(&self) -> bool

Return true if the repository contains no entities.

Trait Implementations

impl<T: CacheEntity> DataRepository<T> for InMemoryRepository<T>

async fn fetch_by_id(&self, id: &T::Key) -> Result<Option<T>>

Fetch entity by ID from primary data source.

async fn fetch_by_ids(&self, ids: &[T::Key]) -> Result<Vec<Option<T>>>

Batch fetch entities by IDs (optional optimization).

async fn count(&self) -> Result<u64>

Count total entities (optional, for statistics).

async fn fetch_all(&self) -> Result<Vec<T>>

Optional: Get all entities (use sparingly, potentially large result).

impl<T: CacheEntity> Default for InMemoryRepository<T>

fn default() -> Self

Returns the “default value” for a type.