#Testing

Krate ships no test runner of its own. This guide shows how to test a Krate app with the tools you already use.

#Compiler-enforced checks

The fastest feedback loop is the compiler itself:

krate build        # fails on compile errors
krate types        # regenerate route/content types
npx tsc --noEmit   # typecheck the app
krate check        # a11y/SEO/perf quality gates

Put these in CI so a bad page can't merge. See Quality Checks and Typed Routes.

#Unit-testing logic

Component logic is plain TypeScript functions, so you can test it without a DOM. Extract logic into modules and test with Vitest:

npm i -D vitest

// src/lib/cart.test.ts
import { describe, it, expect } from "vitest";
import { addItem } from "./cart";

describe("addItem", () => {
  it("appends", () => {
    expect(addItem([], { id: "a" })).toHaveLength(1);
  });
});

#Testing components

Krate components are functions that return JSX trees, not React elements. You can call a component and inspect the tree the same way the compiler does, or render it to a string on the client. For DOM behavior, use a DOM environment:

npm i -D vitest happy-dom

// vitest.config.ts
import { defineConfig } from "vitest/config";
export default defineConfig({ test: { environment: "happy-dom" } });

import { describe, it, expect } from "vitest";
import { createSignal, createEffect } from "@krate/runtime";

describe("signals", () => {
  it("tracks updates", () => {
    const [n, setN] = createSignal(0);
    const seen: number[] = [];
    createEffect(() => seen.push(n()));
    setN(1);
    expect(seen).toContain(1);
  });
});

#End-to-end tests

Build the site and serve the output, then run a browser test (Playwright) or curl/fetch assertions against the rendered HTML:

krate build
krate serve   # serves dist + sidecars

Static pages are plain HTML, so most assertions are just string/DOM checks on dist/**/index.html.

#Testing API routes

src/api/.ts handlers are ordinary functions. With the embedded QuickJS runtime they run in-process; for Node semantics, test the compiled dist/api/.js directly with Node.

#See also

• Quality Checks
• Error Handling
• Deployment