feat: implement import functionality for projects and scenarios with CSV/XLSX support, including validation and error handling

tests/test_import_parsing.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+
+from io import BytesIO
+
+import pandas as pd
+import pytest
+
+from services.importers import ImportResult, load_project_imports, load_scenario_imports
+from schemas.imports import ProjectImportRow, ScenarioImportRow
+
+
+def test_load_project_imports_from_csv() -> None:
+    csv_content = (
+        "name,location,operation_type,description\n"
+        "Project A,Chile,open pit,First project\n"
+        "Project B,,underground,Second project\n"
+    )
+    stream = BytesIO(csv_content.encode("utf-8"))
+
+    result = load_project_imports(stream, "projects.csv")
+
+    assert isinstance(result, ImportResult)
+    assert len(result.rows) == 2
+    assert not result.errors
+    first = result.rows[0]
+    assert first.row_number == 2
+    assert isinstance(first.data, ProjectImportRow)
+    assert first.data.name == "Project A"
+    assert first.data.operation_type.value == "open_pit"
+    second = result.rows[1]
+    assert second.row_number == 3
+    assert isinstance(second.data, ProjectImportRow)
+    assert second.data.location is None
+
+
+def test_load_scenario_imports_from_excel() -> None:
+    df = pd.DataFrame(
+        [
+            {
+                "project_name": "Project A",
+                "name": "Scenario 1",
+                "status": "Active",
+                "start_date": "2025-01-01",
+                "end_date": "2025-12-31",
+                "discount_rate": "7.5%",
+                "currency": "usd",
+                "primary_resource": "Electricity",
+            }
+        ]
+    )
+    buffer = BytesIO()
+    df.to_excel(buffer, index=False)
+    buffer.seek(0)
+
+    result = load_scenario_imports(buffer, "scenarios.xlsx")
+
+    assert len(result.rows) == 1
+    assert not result.errors
+    row = result.rows[0]
+    assert row.row_number == 2
+    assert isinstance(row.data, ScenarioImportRow)
+    assert row.data.status.value == "active"
+    assert row.data.currency == "USD"
+    assert row.data.discount_rate == pytest.approx(7.5)
+
+
+def test_import_errors_include_row_numbers() -> None:
+    csv_content = "name,operation_type\n,open pit\n"
+    stream = BytesIO(csv_content.encode("utf-8"))
+
+    result = load_project_imports(stream, "projects.csv")
+
+    assert len(result.rows) == 0
+    assert len(result.errors) == 1
+    error = result.errors[0]
+    assert error.row_number == 2
+    assert error.field == "name"
+    assert "required" in error.message