Add unit tests for pluralize

extensions/ql-vscode/test/pure-tests/word.test.ts

@@ -0,0 +1,17 @@
+import { expect } from 'chai';
+
+import { pluralize } from '../../src/pure/word';
+
+describe('word helpers', () => {
+  describe('pluralize', () => {
+    it('should return the plural form if the number is 0', () => {
+      expect(pluralize(0, 'thing', 'things')).to.eq('0 things');
+    });
+    it('should return the singular form if the number is 1', () => {
+      expect(pluralize(1, 'thing', 'things')).to.eq('1 thing');
+    });
+    it('should return the plural form if the number is greater than 1', () => {
+      expect(pluralize(7, 'thing', 'things')).to.eq('7 things');
+    });
+  });
+});