Add tests for the api cache and refactor

Signed-off-by: Axel Boberg <[email protected]>

api/classes/Cache.js

@@ -43,6 +43,29 @@ class Cache {
     this.#index.delete(firstKey)
   }
 
+  /**
+   * Get a cached value
+   * by its key
+   * @param { String } key
+   * @returns { Promise.<any> }
+   */
+  get (key) {
+    const entry = this.#index.get(key)
+
+    /*
+    If there is a pending promise for the value,
+    return that rather than starting a new request
+    */
+    if (
+      entry &&
+      entry.status === 'pending' &&
+      entry.promise
+    ) {
+      return entry.promise
+    }
+    return Promise.resolve(this.#index.get(key)?.value)
+  }
+
   /**
    * Cache the response of a provider function,
    * the response will be returned if there's
@@ -72,20 +95,7 @@ class Cache {
     }
 
     if (this.#index.has(key)) {
-      const entry = this.#index.get(key)
-
-      /*
-      If there is a pending promise for the value,
-      return that rather than starting a new request
-      */
-      if (
-        entry &&
-        entry.status === 'pending' &&
-        entry.promise
-      ) {
-        return entry.promise
-      }
-      return this.#index.get(key)?.value
+      return this.get(key)
     }
 
     /*

api/classes/Cache.unit.test.js

@@ -0,0 +1,21 @@
+// SPDX-FileCopyrightText: 2022 Sveriges Television AB
+//
+// SPDX-License-Identifier: MIT
+
+const Cache = require('./Cache')
+const cache = new Cache(5)
+
+test('cache a provider', () => {
+  cache.cache('myKey', () => 10)
+  expect(cache.get('myKey')).resolves.toBe(10)
+})
+
+test('respect the max entry count', () => {
+  cache.cache('myKey1', () => 10)
+  cache.cache('myKey2', () => 10)
+  cache.cache('myKey3', () => 10)
+  cache.cache('myKey4', () => 10)
+  cache.cache('myKey5', () => 10)
+  cache.cache('myKey6', () => 10)
+  expect(cache.get('myKey1')).resolves.toBe(undefined)
+})