Step 89: file watching and auto-reload

editor/tests/step89_test.cpp

@@ -0,0 +1,44 @@
+// Step 89 TDD Test: FileWatcher
+//
+// Tests:
+// 1. Detects change on file modification
+
+#include <cassert>
+#include <iostream>
+#include <filesystem>
+#include <fstream>
+#include <thread>
+#include <chrono>
+#include "FileWatcher.h"
+
+int main() {
+    int passed = 0;
+    int failed = 0;
+
+    std::filesystem::path root = std::filesystem::current_path() / "tmp_step89";
+    std::filesystem::create_directories(root);
+    std::filesystem::path file = root / "file.txt";
+    {
+        std::ofstream f(file.string());
+        f << "a";
+    }
+
+    FileWatcher watcher;
+    watcher.watch(file.string());
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(10));
+    {
+        std::ofstream f(file.string());
+        f << "b";
+    }
+
+    auto changed = watcher.poll();
+    assert(!changed.empty());
+    std::cout << "Test 1 PASS: Change detected" << std::endl;
+    ++passed;
+
+    std::filesystem::remove_all(root);
+
+    std::cout << "\n=== Step 89 Results: " << passed << " passed, " << failed << " failed ===" << std::endl;
+    return failed > 0 ? 1 : 0;
+}