Add CircularList and basic tests

Part of #361

src/utils/CircularList.test.ts

@@ -0,0 +1,81 @@
+import { assert } from 'chai';
+import { CircularList } from './CircularList';
+
+describe('CircularList', () => {
+  describe('push', () => {
+    it('should push values onto the array', () => {
+      const list = new CircularList<string>(5);
+      list.push('1');
+      list.push('2');
+      list.push('3');
+      list.push('4');
+      list.push('5');
+      assert.equal(list.get(0), '1');
+      assert.equal(list.get(1), '2');
+      assert.equal(list.get(2), '3');
+      assert.equal(list.get(3), '4');
+      assert.equal(list.get(4), '5');
+    });
+
+    it('should push old values from the start out of the array when max length is reached', () => {
+      const list = new CircularList<string>(2);
+      list.push('1');
+      list.push('2');
+      assert.equal(list.get(0), '1');
+      assert.equal(list.get(1), '2');
+      list.push('3');
+      assert.equal(list.get(0), '2');
+      assert.equal(list.get(1), '3');
+      list.push('4');
+      assert.equal(list.get(0), '3');
+      assert.equal(list.get(1), '4');
+    });
+  });
+
+  describe('maxLength', () => {
+    it('should increase the size of the list', () => {
+      const list = new CircularList<string>(2);
+      list.push('1');
+      list.push('2');
+      assert.equal(list.get(0), '1');
+      assert.equal(list.get(1), '2');
+      list.maxLength = 4;
+      list.push('3');
+      list.push('4');
+      assert.equal(list.get(0), '1');
+      assert.equal(list.get(1), '2');
+      assert.equal(list.get(2), '3');
+      assert.equal(list.get(3), '4');
+      list.push('wrapped');
+      assert.equal(list.get(0), '2');
+      assert.equal(list.get(1), '3');
+      assert.equal(list.get(2), '4');
+      assert.equal(list.get(3), 'wrapped');
+    });
+
+    it('should return the maximum length of the list', () => {
+      const list = new CircularList<string>(2);
+      assert.equal(list.maxLength, 2);
+      list.push('1');
+      list.push('2');
+      assert.equal(list.maxLength, 2);
+      list.push('3');
+      assert.equal(list.maxLength, 2);
+      list.maxLength = 4;
+      assert.equal(list.maxLength, 4);
+    });
+  });
+
+  describe('length', () => {
+    it('should return the current length of the list, capped at the maximum length', () => {
+      const list = new CircularList<string>(2);
+      assert.equal(list.length, 0);
+      list.push('1');
+      assert.equal(list.length, 1);
+      list.push('2');
+      assert.equal(list.length, 2);
+      list.push('3');
+      assert.equal(list.length, 2);
+    });
+  });
+});