Add tests for LlmSession and LlmSessionCaptionsAndKeywords in both integration and mocked scenarios (#12)

Reviewed-on: #12
Co-authored-by: Mathias Scheider <mathias2784@web.de>

test/conftest.py

@@ -12,9 +12,11 @@ def test_photo():
 
 @pytest.fixture
 def llm_session():
-    return LlmSession(
-        system_prompt=(
-            "You are a helpful assistent to photographer. "
-            'Answer in JSON format: `{"caption": "...", "tags": ["tag1", "tag2", ...]}`'
-        )
-    )
+    return LlmSession(system_prompt="You are a helpful assistant.")
+
+
+@pytest.fixture
+def llm_session_captions_and_keywords():
+    from photools3.llm_session import LlmSessionCaptionsAndKeywords
+
+    return LlmSessionCaptionsAndKeywords()