Tests added.

Some bug solved.

tests/test_app_engine.py

@@ -0,0 +1,72 @@
+import logging
+import pytest
+from unittest.mock import Mock
+
+from appengine import AppEngine
+
+
+@pytest.fixture
+def app():
+    ae = AppEngine("test_app")
+    ae.cl = Mock()  # prevent NoneType error in wait_stop before exec() is called
+    yield ae
+    ae.stop()
+    ae.stop_thread.join(timeout=2)
+
+
+class TestInit:
+    def test_creates_logger(self, app):
+        assert isinstance(app.log, logging.Logger)
+
+    def test_log_level_warning_by_default(self, app):
+        assert app.log.level == logging.WARNING
+
+    def test_log_level_debug_when_requested(self):
+        ae = AppEngine("test_debug", debug=True)
+        ae.cl = Mock()
+        assert ae.log.level == logging.DEBUG
+        ae.stop()
+        ae.stop_thread.join(timeout=2)
+
+    def test_stop_thread_is_alive(self, app):
+        assert app.stop_thread.is_alive()
+
+
+class TestParseConfig:
+    def test_valid_config_file(self, tmp_path):
+        cf = tmp_path / "config.ini"
+        cf.write_text("[general]\ndefault = mymod\n")
+        ae = AppEngine("test_cfg")
+        ae.cl = Mock()
+        ae.parse_config(str(cf))
+        assert ae.conf["general"]["default"] == "mymod"
+        ae.stop()
+        ae.stop_thread.join(timeout=2)
+
+    def test_missing_config_raises(self, app):
+        with pytest.raises(Exception, match="not found"):
+            app.parse_config("/nonexistent/config.ini")
+
+
+class TestDefLog:
+    def test_valid_log_file_adds_file_handler(self, tmp_path):
+        log_file = str(tmp_path / "test.log")
+        ae = AppEngine("test_logfile", log_file=log_file)
+        ae.cl = Mock()
+        assert any(isinstance(h, logging.FileHandler) for h in ae.log.handlers)
+        ae.stop()
+        ae.stop_thread.join(timeout=2)
+        for h in ae.log.handlers:
+            h.close()
+
+
+class TestStop:
+    def test_stop_sets_event(self, app):
+        assert not app.stop_event.is_set()
+        app.stop()
+        assert app.stop_event.is_set()
+
+    def test_stop_thread_exits_after_stop(self, app):
+        app.stop()
+        app.stop_thread.join(timeout=2)
+        assert not app.stop_thread.is_alive()