tests: hello world playground run with success and failure tests (#2513)

Implement two tests for the rust playground:
- successful run of the hello world example with the hello world message
in stdout and a hidden stderr
- on purpose compilation error is shown in stderr and "No output" in
stdout

.github/workflows/build.yml

@@ -189,6 +189,7 @@ jobs:
         run: npm install
         working-directory: ./tests
       - name: Test Javascript
+        if: matrix.language == 'en'
         run: npm test
         env:
           TEST_BOOK_DIR: ../book/comprehensive-rust-${{ matrix.language }}/html

tests/package.json

@@ -3,10 +3,10 @@
   "type": "module",
   "devDependencies": {
     "@types/mocha": "^10.0.10",
-    "@wdio/cli": "^9.3.0",
-    "@wdio/local-runner": "^9.3.0",
-    "@wdio/mocha-framework": "^9.2.8",
-    "@wdio/static-server-service": "^9.2.2"
+    "@wdio/cli": "^9.5.3",
+    "@wdio/local-runner": "^9.5.3",
+    "@wdio/mocha-framework": "^9.5.0",
+    "@wdio/static-server-service": "^9.5.0"
   },
   "scripts": {
     "start": "npm run test",

tests/src/playground.test.ts

@@ -0,0 +1,59 @@
+import { describe, it } from "mocha";
+import { $, expect, browser } from "@wdio/globals";
+import { Key } from "webdriverio";
+
+describe("Playground", () => {
+  it("executes the hello world code and prints the hello message", async () => {
+    await browser.url("/hello-world/hello-world.html");
+    const playground_area = $(".ace_content");
+    const playground_start_button = $("button.play-button");
+    const playground_stderr = $("code.result.stderr");
+    const playground_stdout = $("code.result.stdout");
+
+    // ensure a playground exists and pre-state is as expected
+    await expect(playground_area).toExist();
+    await expect(playground_start_button).toExist();
+    await expect(playground_start_button).not.toBeDisplayed();
+    await expect(playground_stderr).not.toExist();
+    await expect(playground_stdout).not.toExist();
+
+    // clicking into the content is necessary for the button to be displayed
+    await playground_area.waitForClickable();
+    await playground_area.click();
+    await expect(playground_start_button).toBeDisplayed();
+
+    // clicking the button triggers action
+    await playground_start_button.waitForClickable();
+    await playground_start_button.click();
+    await expect(playground_stdout).toBeDisplayed();
+    await expect(playground_stderr).not.toBeDisplayed();
+    await expect(playground_stdout).toHaveText(expect.stringContaining("🌍"));
+  });
+
+  it("shows error messages in stderr if the code is broken", async () => {
+    await browser.url("/hello-world/hello-world.html");
+    const playground_area = $(".ace_content");
+    const playground_start_button = $("button.play-button");
+    const playground_stderr = $("code.result.stderr");
+    const playground_stdout = $("code.result.stdout");
+
+    // clicking into the content is necessary for the button to be displayed
+    await playground_area.waitForClickable();
+    await playground_area.click();
+
+    // append some failing code to the editor that is now in focus
+    await browser.keys([Key.Enter, "fn expect_failure()"]);
+
+    // clicking the button triggers action
+    await playground_start_button.waitForClickable();
+    await playground_start_button.click();
+    await expect(playground_stdout).toBeDisplayed();
+    await expect(playground_stderr).toBeDisplayed();
+
+    // check for error message in stderr
+    await expect(playground_stderr).toHaveText(
+      expect.stringContaining("error: could not compile")
+    );
+    await expect(playground_stdout).toHaveText("No output");
+  });
+});

tests/wdio.conf.ts

@@ -201,8 +201,9 @@ export const config: WebdriverIO.Config = {
    * @param {Array.<String>} specs        List of spec file paths that are to be run
    * @param {object}         browser      instance of created browser/device session
    */
-  // before: function (capabilities, specs) {
-  // },
+  before: function (capabilities, specs) {
+    browser.setWindowSize(2560, 1440);
+  },
   /**
    * Runs before a WebdriverIO command gets executed.
    * @param {string} commandName hook command name