feat: add Gemini-powered birdseye rendering

tests/test_gemini_image.py

@@ -0,0 +1,122 @@
+from __future__ import annotations
+
+from unittest.mock import MagicMock
+
+import pytest
+from PIL import Image as PILImage
+
+
+def test_service_defaults_to_nano_banana_pro_model() -> None:
+    from civilplan_mcp.services.gemini_image import GeminiImageService
+
+    service = GeminiImageService(api_key="test-key", client=MagicMock())
+
+    assert service.api_key == "test-key"
+    assert service.model == "gemini-3-pro-image-preview"
+
+
+def test_service_requires_sdk_or_client() -> None:
+    from civilplan_mcp.services import gemini_image
+    from civilplan_mcp.services.gemini_image import GeminiImageService
+
+    original_genai = gemini_image.genai
+    gemini_image.genai = None
+    try:
+        with pytest.raises(RuntimeError):
+            GeminiImageService(api_key="test-key")
+    finally:
+        gemini_image.genai = original_genai
+
+
+def test_generate_image_calls_api_and_saves_output(tmp_path) -> None:
+    from civilplan_mcp.services.gemini_image import GeminiImageService
+
+    mock_client = MagicMock()
+    mock_image = MagicMock()
+    mock_part = MagicMock()
+    mock_part.inline_data = MagicMock()
+    mock_part.text = None
+    mock_part.as_image.return_value = mock_image
+    mock_client.models.generate_content.return_value = MagicMock(parts=[mock_part])
+
+    service = GeminiImageService(api_key="test-key", client=mock_client)
+    output_path = tmp_path / "generated.png"
+
+    result = service.generate_image(
+        prompt="Generate a bird's-eye render of a Korean road project.",
+        output_path=str(output_path),
+        aspect_ratio="16:9",
+        image_size="2K",
+    )
+
+    assert result["status"] == "success"
+    assert result["path"] == str(output_path)
+    mock_image.save.assert_called_once_with(str(output_path))
+    call_kwargs = mock_client.models.generate_content.call_args.kwargs
+    assert call_kwargs["model"] == "gemini-3-pro-image-preview"
+    assert call_kwargs["contents"] == ["Generate a bird's-eye render of a Korean road project."]
+    assert call_kwargs["config"] is not None
+
+
+def test_generate_image_with_reference_includes_image_content(tmp_path) -> None:
+    from civilplan_mcp.services.gemini_image import GeminiImageService
+
+    reference_path = tmp_path / "reference.png"
+    PILImage.new("RGB", (8, 8), "gray").save(reference_path)
+
+    mock_client = MagicMock()
+    mock_image = MagicMock()
+    mock_part = MagicMock()
+    mock_part.inline_data = MagicMock()
+    mock_part.text = None
+    mock_part.as_image.return_value = mock_image
+    mock_client.models.generate_content.return_value = MagicMock(parts=[mock_part])
+
+    service = GeminiImageService(api_key="test-key", client=mock_client)
+    output_path = tmp_path / "generated.png"
+
+    result = service.generate_image(
+        prompt="Generate a road perspective render.",
+        output_path=str(output_path),
+        reference_image_path=str(reference_path),
+    )
+
+    assert result["status"] == "success"
+    contents = mock_client.models.generate_content.call_args.kwargs["contents"]
+    assert len(contents) == 2
+    assert contents[0] == "Generate a road perspective render."
+
+
+def test_generate_image_returns_error_on_api_failure(tmp_path) -> None:
+    from civilplan_mcp.services.gemini_image import GeminiImageService
+
+    mock_client = MagicMock()
+    mock_client.models.generate_content.side_effect = RuntimeError("API error")
+    service = GeminiImageService(api_key="test-key", client=mock_client)
+
+    result = service.generate_image(
+        prompt="Generate a river project render.",
+        output_path=str(tmp_path / "generated.png"),
+    )
+
+    assert result["status"] == "error"
+    assert "API error" in result["error"]
+
+
+def test_generate_image_returns_error_when_response_has_no_image(tmp_path) -> None:
+    from civilplan_mcp.services.gemini_image import GeminiImageService
+
+    mock_client = MagicMock()
+    mock_part = MagicMock()
+    mock_part.inline_data = None
+    mock_part.text = "No image available."
+    mock_client.models.generate_content.return_value = MagicMock(parts=[mock_part])
+    service = GeminiImageService(api_key="test-key", client=mock_client)
+
+    result = service.generate_image(
+        prompt="Generate a building render.",
+        output_path=str(tmp_path / "generated.png"),
+    )
+
+    assert result["status"] == "error"
+    assert "no image" in result["error"].lower()