feat(web): re-implement timeout error test

The previous approach with overriding `onload` no longer works if we use
indirect eval. However, since we now need to use a server anyways instead
of directly loading a file (because of Core), we can add a timeout to
the test server and implement this test in a cleaner way.

web/src/test/manual/README.md

@@ -0,0 +1,10 @@
+# Manual tests
+
+To run the the manual tests, start the test web server with:
+
+```bash
+cd $KEYMAN_ROOT
+web/build.sh start
+```
+
+Then open <http://localhost:3000> in your browser.

web/src/test/manual/web/keyboard-errors/errorhdr.js

@@ -1,42 +1,42 @@
-// JavaScript Document samplehdr.js: Keyboard management for KeymanWeb demonstration pages
-
-/* 
+/*
     This script is designed to test KeymanWeb error message handling.
 */
 
-  function loadKeyboards() 
-  { 
+  function loadKeyboards()
+  {
     var kmw=keyman;
-    
+
     // We start by adding a keyboard correctly.  It's best to include a 'control' in our experiment.
     kmw.addKeyboards({id:'us',name:'English',languages:{id:'en',name:'English'},
       filename:'../us-1.0.js'});
-      
+
     // Insert a keyboard that cannot be found.
     kmw.addKeyboards({id:'lao_2008_basic',name:'wrong-filename',
       languages:{
         id:'lo',name:'debugging',region:'Asia',
         font:{family:'LaoWeb',source:['../font/saysettha_web.ttf','../font/saysettha_web.woff','../font/saysettha_web.eot']}
         },
       filename:'./missing_file.js' // Intentional error - the file doesn't exist, so the <script> tag will raise an error event.
-      });   
-	  
-	// Insert a keyboard that will generate a timing error.  
+    });
+
+    // Insert a keyboard that will generate a timing error.
     kmw.addKeyboards({id:'unparsable',name:'non-parsable',
       languages:{
         id:'lo',name:'debugging',region:'Asia',
         font:{family:'LaoWeb',source:['../font/saysettha_web.ttf','../font/saysettha_web.woff','../font/saysettha_web.eot']}
         },
       filename:'./unparsable.js' // Intentional error - the file has no parsable keyboard, so while the <script> tag will load,
         // registration will fail.
-      });
+    });
 
-	// Insert a keyboard that will generate a timing error.  
+    // Insert a keyboard that will generate a timing error. `timeout.js` doesn't
+    // exist, but the test server (web/src/tools/testing/test-server/index.cjs)
+    // has special handling for that URL and times out after 10 seconds.
     kmw.addKeyboards({id:'timeout',name:'timeout',
       languages:{
         id:'lo',name:'debugging',region:'Asia',
         font:{family:'LaoWeb',source:['../font/saysettha_web.ttf','../font/saysettha_web.woff','../font/saysettha_web.eot']}
         },
       filename:'./timeout.js' // Intentional (simulated) error - the file never loads, simulating a server timeout.
-      }); 
+    });
   }

web/src/test/manual/web/keyboard-errors/index.html

@@ -65,9 +65,32 @@ <h3>Type in your language in this text area:</h3>
     <h3>or in this input field:</h3>
     <input class='test' value='' placeholder='or here'/>
 
+    <h2>Expected error messages:</h2>
+    <ul>
+      <li><i>wrong-filename</i> keyboard: "Unable to download wrong-filename keyboard for debugging"</li>
+      <li><i>non-parsable</i> keyboard: "Error registering the non-parsable keyboard for debugging; keyboard script at ./unparsable.js may contain an error."</li>
+      <li><i>timeout</i> keyboard: "Sorry, the timeout keyboard for debugging is not currently available."</li>
+    </ul>
+
     <h3><a href="../index.html">Return to testing home page</a></h3>
   </div>
 
+    <script>
+      if (!window.location.href.startsWith('http://localhost:3000')) {
+        const body = document.getElementsByTagName('body')[0];
+        body.innerHTML = `<h1>KeymanWeb Sample Page - Error Testing page</h1>
+        <h2>Unable to load this test page!</h2>
+        <p>This page has to be loaded through the local test server.</p>
+        <p>Do the following:</p>
+        <ol>
+          <li>Open a terminal and navigate to the Keyman source root directory</li>
+          <li>Start the test server with <code>web/build.sh start</code></li>
+          <li>Open <a href="http://localhost:3000/src/test/manual/web/keyboard-errors/index.html">http://localhost:3000/src/test/manual/web/keyboard-errors/index.html</a> in a browser</li>
+        </ol>
+        `;
+      }
+    </script>
+
   </body>
 
   <!--

web/src/tools/testing/test-server/index.cjs

@@ -5,8 +5,21 @@ const port = 3000
 
 app.use(express.static(path.join(__dirname, '../../../../')))
 
+// for testing timeout error in web/src/test/manual/web/keyboard-errors
+const router = express.Router()
+router.get('/src/test/manual/web/keyboard-errors/timeout.js', async (req, res, next) => {
+  console.log('timeout.js requested')
+  return new Promise(() => {
+    setTimeout(() => {
+      res.set('Content-Type', 'application/json');
+      res.status(200);
+
+      next();
+    }, 10500); // > ContextManagerBase.TIMEOUT_THRESHOLD (10 seconds)
+  });
+})
+app.use(router)
+
 app.listen(port, () => {
   console.log(`Keyman test app listening on port ${port}`)
 })
-
-