Reorganize test cases

ts/test-node/util/setUtil_test.ts

@@ -0,0 +1,102 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { difference, isEqual, remove, toggle } from '../../util/setUtil';
+
+describe('set utilities', () => {
+  const original = new Set([1, 2, 3]);
+
+  describe('isEqual', () => {
+    it('returns false if the sets are different', () => {
+      const sets = [
+        new Set([1, 2, 3]),
+        new Set([1, 2, 3, 4]),
+        new Set([1, 2]),
+        new Set([4, 5, 6]),
+      ];
+
+      for (const a of sets) {
+        for (const b of sets) {
+          if (a !== b) {
+            assert.isFalse(isEqual(a, b));
+          }
+        }
+      }
+    });
+
+    it('returns true if both arguments are the same set', () => {
+      const set = new Set([1, 2, 3]);
+      assert.isTrue(isEqual(set, set));
+    });
+
+    it('returns true if the sets have the same values', () => {
+      assert.isTrue(isEqual(new Set(), new Set()));
+      assert.isTrue(isEqual(new Set([1, 2]), new Set([2, 1])));
+    });
+  });
+
+  describe('remove', () => {
+    it('accepts zero arguments, returning a new set', () => {
+      const result = remove(original);
+      assert.deepStrictEqual(result, original);
+      assert.notStrictEqual(result, original);
+    });
+
+    it('accepts 1 argument, returning a new set', () => {
+      const result = remove(original, 2);
+      assert.deepStrictEqual(result, new Set([1, 3]));
+      assert.deepStrictEqual(original, new Set([1, 2, 3]));
+    });
+
+    it('accepts multiple arguments, returning a new set', () => {
+      const result = remove(original, 1, 2, 99);
+      assert.deepStrictEqual(result, new Set([3]));
+      assert.deepStrictEqual(original, new Set([1, 2, 3]));
+    });
+  });
+
+  describe('toggle', () => {
+    it('returns a clone if trying to remove an item that was never there', () => {
+      const result = toggle(original, 99, false);
+      assert.deepStrictEqual(result, new Set([1, 2, 3]));
+      assert.notStrictEqual(result, original);
+    });
+
+    it('returns a clone if trying to add an item that was already there', () => {
+      const result = toggle(original, 3, true);
+      assert.deepStrictEqual(result, new Set([1, 2, 3]));
+      assert.notStrictEqual(result, original);
+    });
+
+    it('can add an item to a set', () => {
+      const result = toggle(original, 4, true);
+      assert.deepStrictEqual(result, new Set([1, 2, 3, 4]));
+      assert.deepStrictEqual(original, new Set([1, 2, 3]));
+    });
+
+    it('can remove an item from a set', () => {
+      const result = toggle(original, 2, false);
+      assert.deepStrictEqual(result, new Set([1, 3]));
+      assert.deepStrictEqual(original, new Set([1, 2, 3]));
+    });
+  });
+
+  describe('difference', () => {
+    it('returns the difference of two sets', () => {
+      assert.deepStrictEqual(
+        difference(new Set(['a', 'b', 'c']), new Set(['a', 'b', 'c'])),
+        new Set()
+      );
+      assert.deepStrictEqual(
+        difference(new Set(['a', 'b', 'c']), new Set([])),
+        new Set(['a', 'b', 'c'])
+      );
+      assert.deepStrictEqual(
+        difference(new Set(['a', 'b', 'c']), new Set(['d'])),
+        new Set(['a', 'b', 'c'])
+      );
+    });
+  });
+});