fix: support test timeouts if the test takes long or never completes

node exits process if unresolved promises are present, for example, listening for a never fired DOM event in jsdom will terminate the process with no errors given, also see nodejs/promises-debugging#16

.watestrc.js

@@ -18,6 +18,11 @@ const cfg = {
    */
   log_dir: process.env.WATEST_LOG_DIR,
 
+  /**
+   * If a test takes longer than the given number, the test will fail.
+   */
+  timeout: process.env.WATEST_TIMEOUT,
+
   /**
    * Temporary storage dir. Recreated each test run. Shall be used to store
    * files generated by tests if any.

core/series.js

@@ -637,7 +637,23 @@ class Series {
       let start_time = new Date();
       try {
         this.core.setExpectedFailures(failures_info);
-        await func(); // execute the test
+
+        // If timeout is given then race it against the test.
+        if (settings.timeout) {
+          let kungFuDeathGripTimer = 0;
+          let kungFuDeathGrip = new Promise(r => {
+            kungFuDeathGripTimer = setTimeout(r, settings.timeout);
+          }).then(() =>
+            fail(
+              `Test ${name} takes longer than ${settings.timeout}ms. It's either slow or never ends.`
+            )
+          );
+
+          await Promise.race([func(), kungFuDeathGrip]);
+          clearTimeout(kungFuDeathGripTimer);
+        } else {
+          await func(); // execute the test
+        }
       } catch (e) {
         let failmsg = e;
         if (e instanceof Error) {

core/settings.js

@@ -50,6 +50,10 @@ class Settings {
     return parseInt(rc.debunk_limit) || 5;
   }
 
+  get timeout() {
+    return parseInt(rc.timeout) || 0;
+  }
+
   setupTmpStorageDir() {
     if (!rc.tmp_dir) {
       console.log(`Settings: no temporary storage dir`);