aider: Patched check_for_model_availability to always return True during setUp method execution.

# Context:
USER: in setup, patch coder.check_for_model_availability to return true
ASSISTANT: To patch the `check_for_model_availability` method in the `setUp` method of the `TestMain` class, you can use the `unittest.mock.patch` context manager. Here's the change you need to make in the `tests/test_main.py` file:

```python
tests/test_main.py
<<<<<<< ORIGINAL
    def setUp(self):
        os.environ["OPENAI_API_KEY"] = "deadbeef"
        self.original_cwd = os.getcwd()
        self.tempdir = tempfile.mkdtemp()
        os.chdir(self.tempdir)
=======
    from unittest.mock import MagicMock

    def setUp(self):
        os.environ["OPENAI_API_KEY"] = "deadbeef"
        self.original_cwd = os.getcwd()
        self.tempdir = tempfile.mkdtemp()
        os.chdir(self.tempdir)

        with patch("aider.coder.Coder.check_for_model_availability") as mock_check:
            mock_check.return_value = True
            self.mock_check = mock_check
>>>>>>> UPDATED
```

This will patch the `check_for_model_availability` method to always return `True` during the `setUp` method execution.

tests/test_main.py

@@ -13,12 +13,18 @@ from aider.main import main
 
 
 class TestMain(TestCase):
+    from unittest.mock import MagicMock
+
     def setUp(self):
         os.environ["OPENAI_API_KEY"] = "deadbeef"
         self.original_cwd = os.getcwd()
         self.tempdir = tempfile.mkdtemp()
         os.chdir(self.tempdir)
 
+        with patch("aider.coder.Coder.check_for_model_availability") as mock_check:
+            mock_check.return_value = True
+            self.mock_check = mock_check
+
     def tearDown(self):
         os.chdir(self.original_cwd)
         shutil.rmtree(self.tempdir)