Added tests for DatabaseConnectionPool class

lib/DatabaseConnectionPool.test.js

@@ -0,0 +1,46 @@
+'use strict';
+
+const DatabaseConnectionPool = require('./DatabaseConnectionPool');
+
+jest.mock('./DatabaseConnectionPool');
+
+describe('DatabaseConnectionPool', () => {
+	test('Should instantiate connection', () => {
+		new DatabaseConnectionPool();
+
+		expect(DatabaseConnectionPool).toHaveBeenCalledTimes(1);
+	});
+
+	test('Non prepared query should not execute with params', () => {
+		const dbp = new DatabaseConnectionPool();
+
+		const sql = `SELECT * FROM class;`;
+		dbp.runQuery(sql);
+
+		expect(dbp.runQuery.mock.results[0].value).toEqual({
+			sql: sql
+		});
+	});
+
+	test('Prepared query should execute along with params', () => {
+		const dbp = new DatabaseConnectionPool();
+
+		const sql = `SELECT * FROM class where name = ?;`;
+		const params = [ 'bob' ];
+		dbp.runQuery(sql, params);
+
+		expect(dbp.runQuery.mock.results[0].value).toEqual({
+			sql: sql,
+			params: params
+		});
+	});
+
+	test('Query without trailing ; should throw error', () => {
+		const dbp = new DatabaseConnectionPool();
+
+		const sql = `SELECT * FROM class where name = ?`;
+		const params = [ 'bob' ];
+
+		expect(() => dbp.runQuery(sql, params)).toThrow();
+	});
+});