Add snowpack as an example project. (#11)

* Initial tests set up

This adds tests using uvu (we can switch if people want) and restructures things a bit so that it's easier to test.

Like in snowpack you set up a little project. In our tests you can say:

```js
const result = await runtime.load('/blog/hello-world')
```

And analyze the result. I included a `test-helpers.js` which has a function that will turn HTML into a cheerio instance, for inspecting the result HTML.

* Bring snowpack example in

* Formatting

1 files changed, 73 insertions, 0 deletions

diff --git a/test/snowpack-integration.test.js b/test/snowpack-integration.test.js
new file mode 100644
index 000000000..d2a75075e
--- /dev/null
+++ b/test/snowpack-integration.test.js
@@ -0,0 +1,73 @@
+import { suite } from 'uvu';
+import * as assert from 'uvu/assert';
+import { createRuntime } from '../lib/runtime.js';
+import { promises as fsPromises } from 'fs';
+import { relative as pathRelative } from 'path';
+import { doc } from './test-utils.js';
+
+const { readdir, stat } = fsPromises;
+
+const SnowpackDev = suite('snowpack.dev');
+
+let runtime;
+
+SnowpackDev.before(async () => {
+  const astroConfig = {
+    projectRoot: new URL('../examples/snowpack/', import.meta.url),
+    hmxRoot: new URL('../examples/snowpack/astro/', import.meta.url),
+    dist: './_site'
+  };
+  
+  const logging = {
+    level: 'error',
+    dest: process.stderr
+  };
+
+  runtime = await createRuntime(astroConfig, logging);
+});
+
+SnowpackDev.after(async () => {
+  await runtime.shutdown();
+});
+
+async function* allPageFiles(root) {
+  for (const filename of await readdir(root)) {
+    const fullpath = new URL(filename, root);
+    const info = await stat(fullpath);
+
+    if (info.isDirectory()) {
+      yield* allPageFiles(new URL(fullpath + '/'));
+    } else {
+      yield fullpath;
+    }
+  }
+}
+
+async function* allPages(root) {
+  for await(let fileURL of allPageFiles(root)) {
+    let bare = fileURL.pathname
+      .replace(/\.(hmx|md)$/, '')
+      .replace(/index$/, '')
+
+    yield '/' + pathRelative(root.pathname, bare);
+  }
+}
+
+SnowpackDev.skip('Can load every page', async () => {
+  const failed = [];
+
+  const pageRoot = new URL('../examples/snowpack/astro/pages/', import.meta.url);
+  for await(let pathname of allPages(pageRoot)) {
+    const result = await runtime.load(pathname);
+    if(result.statusCode === 500) {
+      failed.push(result);
+      continue;
+    }
+    assert.equal(result.statusCode, 200, `Loading ${pathname}`);
+  }
+
+  assert.equal(failed.length, 0, 'Failed pages');
+  console.log(failed);
+});
+
+SnowpackDev.run();
\ No newline at end of file