fix: begin running tests immediately instead of waiting for watcher

lib/cli/watch-run.js

@@ -7,6 +7,7 @@ const chokidar = require('chokidar');
 const Context = require('../context');
 const collectFiles = require('./collect-files');
 const glob = require('glob');
+const fs = require('node:fs');
 
 /**
  * Exports the `watchRun` function that runs mocha in "watch" mode.
@@ -215,23 +216,40 @@ const createWatcher = (
     beforeRun
   });
 
-  watcher.on('ready', async () => {
-    if (!globalFixtureContext) {
-      debug('triggering global setup');
-      globalFixtureContext = await mocha.runGlobalSetup();
-    }
-    rerunner.run();
+  // eslint-disable-next-line no-restricted-globals
+  const startTime = new Date();
+  let ready = false;
+  watcher.on('ready', () => {
+    ready = true;
   });
 
-  watcher.on('all', (event, filePath) => {
-    if (event === 'add') {
-      tracker.regenerate();
+  watcher.on('all', async function handleEvent(event, filePath, stat) {
+    if (exiting) return;
+    if (event === 'unlink' || (stat ? stat.mtime > startTime : ready)) {
+      if (event === 'add') {
+        tracker.regenerate();
+      }
+      // we don't want to accidentally trigger a run before globalFixtureContext
+      // has been created.  If it hasn't then it's okay to do nothing here because
+      // the code that creates globalFixtureContext will run the tests afterward
+      if (tracker.has(filePath) && globalFixtureContext) {
+        rerunner.scheduleRun();
+      }
+      return;
     }
-    if (tracker.has(filePath)) {
-      rerunner.scheduleRun();
+    if (!ready && !stat) {
+      fs.stat(filePath, (err, stat) => {
+        if (stat) handleEvent(event, filePath, stat);
+      });
     }
   });
 
+  debug('triggering global setup');
+  mocha.runGlobalSetup().then(context => {
+    globalFixtureContext = context;
+    rerunner.run();
+  });
+
   hideCursor();
   process.on('exit', () => {
     showCursor();