fix: Properly preserve exit codes in run and run-workers commands

- Use beforeExit handler to set force-exit timeout AFTER Mocha sets exit codes
- This ensures failed tests correctly propagate exit code 1 to parent process
- Also change process.exit(1) to process.exitCode = 1 in error handlers
- Add same force-exit logic to run-workers command for consistency

Fixes test:runner failures where tests expected err.code=1 but got err=null.
The issue was that our previous force-exit implementation called process.exit()
before Mocha's exit handlers could set the correct exit code, causing the
process to always exit with code 0 regardless of test failures.

This fix ensures:
1. Mocha and other exit handlers run first and set correct exit codes
2. Force-exit still happens to prevent hanging from leftover handles
3. Exit codes are properly propagated to parent processes (e.g., in exec())

All 244 test:runner tests now pass.

Author: kobenguyent

lib/command/run-workers.js

@@ -72,8 +72,22 @@ export default async function (workerCount, selectedRuns, options) {
     await workers.run()
   } catch (err) {
     output.error(err)
-    process.exit(1)
+    process.exitCode = 1
   } finally {
     await workers.teardownAll()
+    
+    // Force exit if event loop doesn't clear naturally
+    // This is needed because worker threads may leave handles open
+    // even after proper cleanup, preventing natural process termination
+    if (!options.noExit) {
+      // Use beforeExit to ensure we run after all other exit handlers
+      // have set the correct exit code
+      process.once('beforeExit', (code) => {
+        // Give cleanup a moment to complete, then force exit with the correct code
+        setTimeout(() => {
+          process.exit(code || process.exitCode || 0)
+        }, 100)
+      })
+    }
   }
 }

lib/command/run.js

@@ -47,9 +47,14 @@ export default async function (test, options) {
     // This is needed because some helpers (like Playwright) may leave handles open
     // even after proper cleanup, preventing natural process termination
     if (!options.noExit) {
-      setTimeout(() => {
-        process.exit(process.exitCode || 0)
-      }, 100)
+      // Use beforeExit to ensure we run after all other exit handlers (including Mocha's)
+      // have set the correct exit code
+      process.once('beforeExit', (code) => {
+        // Give cleanup a moment to complete, then force exit with the correct code
+        setTimeout(() => {
+          process.exit(code || process.exitCode || 0)
+        }, 100)
+      })
     }
   }
 }