Write tests for router

src/router_test.tsx

@@ -0,0 +1,70 @@
+// Tests for the router component.
+import { h, render, rerender } from "preact";
+import { testBrowser } from "../tools/tester";
+import { push, Router } from "./router";
+import { assertEqual } from "./util";
+
+const matchedProps = new Map<string, any>();
+
+interface ComponentProps {
+  id: string;
+  matches?: any;
+  path?: string;
+}
+// tslint:disable-next-line:variable-name
+const Test = (props: ComponentProps) => {
+  matchedProps.set(props.id, props.matches);
+  return (
+    <div id={props.id} class="test" />
+  );
+};
+
+testBrowser(async function router() {
+  document.body.innerHTML = "";
+  render(
+    <Router>
+      <Test id="p1" path="/" />
+      <Test id="p2" path="/test" />
+      <Test id="p3" path="/page/:v" />
+      <Test id="p4" path="/test/:v" />
+      <Test id="404" />
+    </Router>
+    , document.body);
+  // .slice(1) is to remove # from the location.hash.
+  const path = () => document.location.hash.slice(1);
+  const activePage = () => {
+    const rendered = document.querySelectorAll(".test");
+    // We must render only one component at each moment.
+    assertEqual(rendered.length, 1);
+    return rendered[0].id;
+  };
+  // Rest path.
+  window.location.hash = "/";
+  await flush();
+  // Initial page.
+  assertEqual(path(), "/");
+  assertEqual(activePage(), "p1");
+  // 404 page.
+  push("/propel");
+  await flush();
+  assertEqual(path(), "/propel");
+  assertEqual(activePage(), "404");
+  // We must not render p2 in this case.
+  push("/test/12345");
+  await flush();
+  assertEqual(path(), "/test/12345");
+  assertEqual(activePage(), "p4");
+  assertEqual(matchedProps.get("p4").v, "12345");
+  // Go to a page with some argument.
+  push("/page/345");
+  await flush();
+  assertEqual(path(), "/page/345");
+  assertEqual(activePage(), "p3");
+  assertEqual(matchedProps.get("p3").v, "345");
+});
+
+// Call this to ensure that the DOM has been updated after events.
+function flush(): Promise<void> {
+  rerender();
+  return Promise.resolve();
+}

src/test.ts

@@ -3,4 +3,5 @@ import "./fetch_test";
 import "./inspector_test";
 import "./nb_test";
 import "./nb_transpiler_test";
+import "./router_test";
 import "./rpc_test";