Issue 7285 - Abstract caching logic

test/caching.js

Index: test/caching.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/test/caching.js
@@ -0,0 +1,112 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+const {createSandbox} = require("./_common");
+
+let Cache = null;
+
+exports.setUp = function(callback)
+{
+  let sandboxedRequire = createSandbox();
+  (
+    {Cache} = sandboxedRequire("../lib/caching")
+  );
+
+  callback();
+};
+
+exports.testCache = function(test)
+{
+  // A capacity must be specificed and it must be coercable to a positive
+  // number greater than or equal to one.
+  test.throws(() => { new Cache(); }, "capacity must be a positive number.");
+  test.throws(() => { new Cache(0); }, "capacity must be a positive number.");
+  test.throws(() => { new Cache(-1); }, "capacity must be a positive number.");
+  test.throws(() => { new Cache(0.1); }, "capacity must be a positive number.");
+  test.throws(() => { new Cache(Number.MIN_VALUE); },
+              "capacity must be a positive number.");
+  test.throws(() => { new Cache(-Infinity); },
+              "capacity must be a positive number.");
+  test.throws(() => { new Cache("ten"); },
+              "capacity must be a positive number.");
+  test.doesNotThrow(() => { new Cache(1); },
+                    "capacity must be a positive number.");
+  test.doesNotThrow(() => { new Cache(1.1); },
+                    "capacity must be a positive number.");
+  test.doesNotThrow(() => { new Cache(10); },
+                    "capacity must be a positive number.");
+  test.doesNotThrow(() => { new Cache(Number.MAX_VALUE); },
+                    "capacity must be a positive number.");
+  test.doesNotThrow(() => { new Cache(Infinity); },
+                    "capacity must be a positive number.");
+  test.doesNotThrow(() => { new Cache("10"); },
+                    "capacity must be a positive number.");
+
+  let cache = new Cache(100);
+
+  cache.set("1", "one");
+  test.equal(cache.get("1"), "one");
+
+  cache.set(2, "two");
+  test.equal(cache.get(2), "two");
+
+  // No type coercion.
+  test.equal(cache.get("2"), undefined);
+
+  // Neither key nor value can be undefined.
+  test.throws(() => { cache.set(undefined, "three"); },
+              "key must not be undefined.");
+  test.throws(() => { cache.set(4, undefined); },
+              "value must not be undefined.");
+
+  // Keys and values can be null.
+  cache.set(null, "five");
+  cache.set(5, null);
+
+  cache.clear();
+
+  test.equal(cache.get("1"), undefined);
+  test.equal(cache.get(2), undefined);
+  test.equal(cache.get(null), undefined);
+  test.equal(cache.get(5), undefined);
+
+  // Fill to capacity.
+  for (let i = 0; i < 100; i++)
+    cache.set(i, i);
+
+  // All entries exist.
+  for (let i = 0; i < 100; i++)
+    test.equal(cache.get(i), i);
+
+  // Add an existing entry again.
+  cache.set(0, 0);
+
+  // All entries still exist.
+  for (let i = 0; i < 100; i++)
+    test.equal(cache.get(i), i);
+
+  // Exceed capacity.
+  cache.set(100, 100);
+
+  // Only the last entry exists.
+  for (let i = 0; i <= 100; i++)
+    test.equal(cache.get(i), i == 100 ? 100 : undefined);
+
+  test.done();
+};