Chapter 17: Testing

1. Why Tests Matter More Than You Think

Friday afternoon. Your client reported a critical bug. You fix it -- one line. But did that fix break something else? The test suite answers in 2 seconds.

npm test

Running tests...

  ProductTest
    [PASS] test_create_product
    [PASS] test_load_product
    [PASS] test_update_product
    [PASS] test_delete_product

  AuthTest
    [PASS] test_login_with_valid_credentials
    [PASS] test_login_with_invalid_password
    [PASS] test_protected_route_without_token

  7 tests, 7 passed, 0 failed (0.34s)

Tina4 ships an inline testing framework. No external packages. No Jest configuration. No setup ceremony.

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2. Your First Test

Tests live in the tests/ directory. The test runner is tests/run-all.ts.

Create tests/BasicTest.ts:

import { Test } from "tina4-nodejs";

export class BasicTest extends Test {
    async testAddition() {
        this.assertEqual(2 + 2, 4, "Basic addition should work");
    }

    async testStringConcatenation() {
        const result = "Hello" + " " + "World";
        this.assertEqual(result, "Hello World", "String concatenation should work");
    }

    async testArrayLength() {
        const items = [1, 2, 3];
        this.assertEqual(items.length, 3, "Array should have 3 items");
    }

    async testBooleanLogic() {
        this.assertTrue(true, "true should be true");
        this.assertFalse(false, "false should be false");
    }
}

Run it:

npm test

Running tests...

  BasicTest
    [PASS] testAddition
    [PASS] testStringConcatenation
    [PASS] testArrayLength
    [PASS] testBooleanLogic

  4 tests, 4 passed, 0 failed (0.01s)

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3. Assertion Methods

Method	Description
assertEqual(actual, expected, message)	Values are equal
assertNotEqual(actual, expected, message)	Values are not equal
assertTrue(value, message)	Value is truthy
assertFalse(value, message)	Value is falsy
assertNull(value, message)	Value is null
assertNotNull(value, message)	Value is not null
assertContains(haystack, needle, message)	String or array contains value
assertThrows(fn, message)	Function throws an error

---

4. Testing Routes with testGet() and testPost()

import { Test } from "tina4-nodejs";

export class ProductApiTest extends Test {
    async testListProducts() {
        const response = await this.testGet("/api/products");

        this.assertEqual(response.status, 200, "Should return 200");
        this.assertNotNull(response.body.products, "Should have products array");
    }

    async testCreateProduct() {
        const response = await this.testPost("/api/products", {
            name: "Test Widget",
            category: "Testing",
            price: 9.99
        });

        this.assertEqual(response.status, 201, "Should return 201");
        this.assertEqual(response.body.name, "Test Widget", "Name should match");
        this.assertEqual(response.body.price, 9.99, "Price should match");
    }

    async testGetProductNotFound() {
        const response = await this.testGet("/api/products/99999");

        this.assertEqual(response.status, 404, "Should return 404");
        this.assertContains(response.body.error, "not found", "Error message should mention not found");
    }

    async testCreateProductValidation() {
        const response = await this.testPost("/api/products", {});

        this.assertEqual(response.status, 400, "Should return 400 for missing name");
    }
}

---

5. Testing with Authentication

import { Test, Auth } from "tina4-nodejs";

export class AuthTest extends Test {
    private token: string = "";

    async setup() {
        // Register and login to get a token
        await this.testPost("/api/register", {
            name: "Test User",
            email: "test@example.com",
            password: "securePass123"
        });

        const loginResponse = await this.testPost("/api/login", {
            email: "test@example.com",
            password: "securePass123"
        });

        this.token = loginResponse.body.token;
    }

    async testProfileWithToken() {
        const response = await this.testGet("/api/profile", {
            headers: { Authorization: `Bearer ${this.token}` }
        });

        this.assertEqual(response.status, 200, "Should return 200 with valid token");
        this.assertEqual(response.body.email, "test@example.com", "Should return correct email");
    }

    async testProfileWithoutToken() {
        const response = await this.testGet("/api/profile");

        this.assertEqual(response.status, 401, "Should return 401 without token");
    }
}

---

6. Testing ORM Models

import { Test } from "tina4-nodejs";
import { Product } from "../src/orm/Product";

export class ProductModelTest extends Test {
    async testCreateAndLoad() {
        const product = new Product();
        product.name = "Test Product";
        product.price = 29.99;
        product.category = "Testing";
        await product.save();

        this.assertNotNull(product.id, "Should have an ID after save");

        const loaded = new Product();
        await loaded.load(product.id);

        this.assertEqual(loaded.name, "Test Product", "Name should match");
        this.assertEqual(loaded.price, 29.99, "Price should match");

        await product.delete();
    }

    async testSoftDelete() {
        const product = new Product();
        product.name = "Deletable";
        product.price = 1.00;
        await product.save();
        const id = product.id;

        await product.delete();

        const loaded = new Product();
        await loaded.load(id);
        this.assertNull(loaded.id, "Soft-deleted product should not be loadable");
    }
}

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7. Test Database Isolation

Tina4 creates a test database (data/test.db) when running tests. Each test class gets a clean database. No leftover data from previous runs.

# In .env.test (optional)
DATABASE_URL=sqlite:///data/test.db

---

8. Setup and Teardown

export class MyTest extends Test {
    async setup() {
        // Runs before each test
    }

    async teardown() {
        // Runs after each test
    }

    async setupOnce() {
        // Runs once before all tests in this class
    }

    async teardownOnce() {
        // Runs once after all tests in this class
    }
}

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9. Running Specific Tests

npm test -- --filter ProductTest
npm test -- --filter testCreateProduct

---

10. Exercise: Write Tests for a Notes API

Write a test class that covers: creating a note, listing notes, getting a single note, updating a note, deleting a note, and validation errors.

---

11. Solution

import { Test } from "tina4-nodejs";

export class NotesApiTest extends Test {
    private noteId: number = 0;

    async testCreateNote() {
        const response = await this.testPost("/api/notes", {
            title: "Test Note",
            content: "This is a test note",
            tag: "testing"
        });
        this.assertEqual(response.status, 201);
        this.assertEqual(response.body.title, "Test Note");
        this.noteId = response.body.id;
    }

    async testListNotes() {
        const response = await this.testGet("/api/notes");
        this.assertEqual(response.status, 200);
        this.assertTrue(response.body.count >= 1, "Should have at least one note");
    }

    async testGetNote() {
        const response = await this.testGet(`/api/notes/${this.noteId}`);
        this.assertEqual(response.status, 200);
        this.assertEqual(response.body.title, "Test Note");
    }

    async testUpdateNote() {
        const response = await this.testPut(`/api/notes/${this.noteId}`, {
            title: "Updated Note"
        });
        this.assertEqual(response.status, 200);
        this.assertEqual(response.body.title, "Updated Note");
    }

    async testDeleteNote() {
        const response = await this.testDelete(`/api/notes/${this.noteId}`);
        this.assertEqual(response.status, 204);
    }

    async testCreateNoteValidation() {
        const response = await this.testPost("/api/notes", {});
        this.assertEqual(response.status, 400);
        this.assertNotNull(response.body.errors);
    }

    async testGetNotFound() {
        const response = await this.testGet("/api/notes/99999");
        this.assertEqual(response.status, 404);
    }
}

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12. Gotchas

1. Tests Must Extend Test Class -- export class MyTest extends Test.

2. Test Methods Must Start with "test" -- testCreateProduct, not createProductTest.

3. All Tests Are Async -- Use async and await for all test methods.

4. Test Order Is Not Guaranteed -- Do not depend on test execution order.

5. Database State Leaks Between Tests -- Use setup() and teardown() to clean up.

6. Missing Assertions -- A test without assertions passes silently. Always assert.

7. Test Files Must Export Classes -- export class MyTest extends Test, not a default export.