Test

Setup and teardown APIs

Setup and teardown APIs

To make testing easier, you can use these APIs to help perform setup and teardown for test cases:

Deno.test.beforeAll
Deno.test.beforeEach
Deno.test.afterAll
Deno.test.afterEach

Here’s a concrete example showing how to set up a test database:

import sqlite from "node:sqlite";
import { assertEquals } from "jsr:@std/assert";

let testDb: sqlite.DatabaseSync;

// Run once before all tests
Deno.test.beforeAll(() => {
  testDb = new sqlite.DatabaseSync(":memory:");
  testDb.exec(`CREATE TABLE users (
      id INTEGER PRIMARY KEY, name TEXT NOT NULL, email TEXT UNIQUE
    );
  `);
});

// Run before each individual test
Deno.test.beforeEach(() => {
  testDb.exec("DELETE FROM users");
  const insert = testDb.prepare(
    "INSERT INTO users (name, email) VALUES (?, ?)",
  );
  insert.run("Alice", "alice@example.com");
  insert.run("Bob", "bob@example.com");
});

// Run after each individual test
Deno.test.afterEach(() => {
  // Clean up test data
  testDb.exec("DELETE FROM users");
});

// Run once after all tests
Deno.test.afterAll(() => {
  testDb.close();
});

Deno.test("should find user by email", () => {
  const query = testDb.prepare("SELECT * FROM users WHERE email = ?");
  const user = query.get("alice@example.com");
  assertEquals(user?.name, "Alice");
});

Deno.test("should create new user", () => {
  const insert = testDb.prepare(
    "INSERT INTO users (name, email) VALUES (?, ?)",
  );
  insert.run("Charlie", "charlie@example.com");

  const countQuery = testDb.prepare("SELECT COUNT(*) as count FROM users");
  const result = countQuery.get();
  assertEquals(result!.count, 3); // 2 from beforeEach + 1 new
});

Deno - Test

Setup and teardown APIs