Add unit tests for LLM init function (#3188)

* Add unit tests for LLM init function

* Fix formatting

---------

Co-authored-by: OpenDevin <opendevin@all-hands.dev>

tests/unit/test_llm.py

@@ -0,0 +1,84 @@
+from unittest.mock import patch
+
+import pytest
+
+from opendevin.core.config import LLMConfig
+from opendevin.core.metrics import Metrics
+from opendevin.llm.llm import LLM
+
+
+@pytest.fixture
+def default_config():
+    return LLMConfig(model='gpt-3.5-turbo', api_key='test_key')
+
+
+def test_llm_init_with_default_config(default_config):
+    llm = LLM(default_config)
+    assert llm.config.model == 'gpt-3.5-turbo'
+    assert llm.config.api_key == 'test_key'
+    assert isinstance(llm.metrics, Metrics)
+
+
+@patch('opendevin.llm.llm.litellm.get_model_info')
+def test_llm_init_with_model_info(mock_get_model_info, default_config):
+    mock_get_model_info.return_value = {
+        'max_input_tokens': 8000,
+        'max_output_tokens': 2000,
+    }
+    llm = LLM(default_config)
+    assert llm.config.max_input_tokens == 8000
+    assert llm.config.max_output_tokens == 2000
+
+
+@patch('opendevin.llm.llm.litellm.get_model_info')
+def test_llm_init_without_model_info(mock_get_model_info, default_config):
+    mock_get_model_info.side_effect = Exception('Model info not available')
+    llm = LLM(default_config)
+    assert llm.config.max_input_tokens == 4096
+    assert llm.config.max_output_tokens == 1024
+
+
+def test_llm_init_with_custom_config():
+    custom_config = LLMConfig(
+        model='custom-model',
+        api_key='custom_key',
+        max_input_tokens=5000,
+        max_output_tokens=1500,
+        temperature=0.8,
+        top_p=0.9,
+    )
+    llm = LLM(custom_config)
+    assert llm.config.model == 'custom-model'
+    assert llm.config.api_key == 'custom_key'
+    assert llm.config.max_input_tokens == 5000
+    assert llm.config.max_output_tokens == 1500
+    assert llm.config.temperature == 0.8
+    assert llm.config.top_p == 0.9
+
+
+def test_llm_init_with_metrics():
+    config = LLMConfig(model='gpt-3.5-turbo', api_key='test_key')
+    metrics = Metrics()
+    llm = LLM(config, metrics=metrics)
+    assert llm.metrics is metrics
+
+
+def test_llm_reset():
+    llm = LLM(LLMConfig(model='gpt-3.5-turbo', api_key='test_key'))
+    initial_metrics = llm.metrics
+    llm.reset()
+    assert llm.metrics is not initial_metrics
+    assert isinstance(llm.metrics, Metrics)
+
+
+@patch('opendevin.llm.llm.litellm.get_model_info')
+def test_llm_init_with_openrouter_model(mock_get_model_info, default_config):
+    default_config.model = 'openrouter:gpt-3.5-turbo'
+    mock_get_model_info.return_value = {
+        'max_input_tokens': 7000,
+        'max_output_tokens': 1500,
+    }
+    llm = LLM(default_config)
+    assert llm.config.max_input_tokens == 7000
+    assert llm.config.max_output_tokens == 1500
+    mock_get_model_info.assert_called_once_with('openrouter:gpt-3.5-turbo')