feat(storage): add InMemoryKVStore, InMemoryStore accepts optional KVStore

src/memory/store.ts

@@ -7,7 +7,35 @@
  * in production by satisfying the same {@link MemoryStore} interface.
  */
 
-import type { MemoryEntry, MemoryStore } from '../types.js'
+import type { KVStore, MemoryEntry, MemoryStore } from '../types.js'
+
+// ---------------------------------------------------------------------------
+// InMemoryKVStore
+// ---------------------------------------------------------------------------
+
+export class InMemoryKVStore implements KVStore {
+  private readonly data = new Map<string, string>()
+
+  async get(key: string): Promise<string | null> {
+    return this.data.get(key) ?? null
+  }
+
+  async set(key: string, value: string): Promise<void> {
+    this.data.set(key, value)
+  }
+
+  async delete(key: string): Promise<void> {
+    this.data.delete(key)
+  }
+
+  async list(): Promise<string[]> {
+    return Array.from(this.data.keys())
+  }
+
+  async clear(): Promise<void> {
+    this.data.clear()
+  }
+}
 
 // ---------------------------------------------------------------------------
 // InMemoryStore
@@ -31,6 +59,8 @@ import type { MemoryEntry, MemoryStore } from '../types.js'
 export class InMemoryStore implements MemoryStore {
   private readonly data = new Map<string, MemoryEntry>()
 
+  constructor(_kvStore?: KVStore) {}
+
   // ---------------------------------------------------------------------------
   // MemoryStore interface
   // ---------------------------------------------------------------------------

tests/kv-store.test.ts

@@ -0,0 +1,45 @@
+import { describe, it, expect } from 'vitest'
+import { InMemoryKVStore } from '../src/memory/store.js'
+
+describe('InMemoryKVStore', () => {
+  it('sets and gets a value', async () => {
+    const store = new InMemoryKVStore()
+    await store.set('k1', 'v1')
+    expect(await store.get('k1')).toBe('v1')
+  })
+
+  it('returns null for missing key', async () => {
+    const store = new InMemoryKVStore()
+    expect(await store.get('nope')).toBeNull()
+  })
+
+  it('overwrites existing key', async () => {
+    const store = new InMemoryKVStore()
+    await store.set('k', 'first')
+    await store.set('k', 'second')
+    expect(await store.get('k')).toBe('second')
+  })
+
+  it('deletes a key', async () => {
+    const store = new InMemoryKVStore()
+    await store.set('k', 'v')
+    await store.delete('k')
+    expect(await store.get('k')).toBeNull()
+  })
+
+  it('list returns all keys', async () => {
+    const store = new InMemoryKVStore()
+    await store.set('a', '1')
+    await store.set('b', '2')
+    const keys = await store.list()
+    expect(keys.sort()).toEqual(['a', 'b'])
+  })
+
+  it('clear removes all keys', async () => {
+    const store = new InMemoryKVStore()
+    await store.set('a', '1')
+    await store.set('b', '2')
+    await store.clear()
+    expect(await store.list()).toEqual([])
+  })
+})