Add basic integration test for aleph dev command

CONTRIBUTING.md

@@ -16,7 +16,7 @@ You will need [Deno](https://deno.land/) 1.13+.
 2. Clone the repository to your local device.
 3. Create a new branch `git checkout -b BRANCH_NAME`.
 4. Change code then run the examples.
-5. Push your branch to Github after all tests passed.
+5. [Push your branch to Github after all tests passed.](#Testing)
 6. Make a [pull request](https://github.com/alephjs/aleph.js/pulls).
 7. Merge to master branch by our maintainers.
 
@@ -29,9 +29,21 @@ ALEPH_DEV=true deno run -A --unstable --location=http://localhost cli.ts start .
 
 # ssg
 ALEPH_DEV=true deno run -A --unstable --location=http://localhost cli.ts build ./examples/hello-world -L debug
+```
+
+## Testing
+
+You can run all tests with the following command:
+
+```bash
+$ deno test -A --unstable --location=http://localhost -c=deno.json --import-map=import_map.json
+```
+
+After running `integration_test.ts`, a zombie subprocesse may remain alive. (See [denoland/deno#7087](https://github.com/denoland/deno/issues/7087) for details) You can get rid of it with the following command:
 
-# run all tests
-deno test -A --unstable --location=http://localhost -c=deno.json --import-map=import_map.json
+```shell
+# On Unix
+$ kill $(lsof -i:8080 -t)
 ```
 
 ## Project Structure

integration_test.ts

@@ -0,0 +1,87 @@
+import {
+  assert,
+  assertEquals,
+  assertStringIncludes
+} from 'std/testing/asserts.ts'
+import { emptyDir } from 'std/fs/mod.ts'
+import { BufReader } from 'std/io/bufio.ts'
+import { DOMParser } from 'https://deno.land/x/[email protected]/deno-dom-wasm.ts'
+
+Deno.test('integration: dev command', async () => {
+  const distDir = './examples/hello-world/dist'
+  await emptyDir(distDir)
+  localStorage.removeItem('count')
+
+  const buildCmd = aleph(['dev', './examples/hello-world', '--port', '8080'])
+  try {
+    const port = await waitForServerToStart(buildCmd)
+
+    // Call /api/counter/increase twice
+    let res = await fetch(`http://localhost:${port}/api/counter/increase`)
+    assert(res.ok)
+    assertEquals(await res.json(), { count: 1 })
+
+    res = await fetch(`http://localhost:${port}/api/counter/increase`)
+    assert(res.ok)
+    assertEquals(await res.json(), { count: 2 })
+
+    // Get index page
+    const parser = new DOMParser()
+    res = await fetch(`http://localhost:${port}`)
+    const html = await res.text()
+    const doc = parser.parseFromString(html, 'text/html')
+    assert(doc)
+
+    const copyinfo = doc.querySelector('.copyinfo')
+    assert(copyinfo)
+    assertStringIncludes(copyinfo.textContent, 'Built by Aleph.js in Deno')
+  } finally {
+    cleanupAlephProcess(buildCmd)
+  }
+})
+
+function aleph(cmd: Array<string>): Deno.Process {
+  return Deno.run({
+    cmd: [
+      Deno.execPath(),
+      'run',
+      '-A',
+      '--unstable',
+      '--location=http://localhost',
+      'cli.ts',
+      ...cmd
+    ],
+    env: {
+      'ALEPH_DEV': 'true',
+      'NO_COLOR': 'true'
+    },
+    stdout: "piped",
+  })
+}
+
+function cleanupAlephProcess(process: Deno.Process): void {
+  if (process.stdout) {
+    process.stdout.close()
+  }
+  process.close()
+}
+
+// Waits for the aleph server to start and returns a port
+async function waitForServerToStart(process: Deno.Process): Promise<number> {
+  assert(process.stdout)
+  const buf = BufReader.create(process.stdout)
+  const decoder = new TextDecoder()
+  while (true) {
+    const result = await buf.readLine()
+    if (result == null) {
+      throw new Error('Unexpected EOF')
+    }
+
+    const { line } = result
+    const match = /^INFO Server ready on http:\/\/localhost:(\d+).*$/.exec(decoder.decode(line))
+    if (match) {
+      const [, port] = match
+      return parseInt(port)
+    }
+  }
+}