ENH: Adapt to stricter project .fmu init behavior

pyproject.toml

@@ -32,7 +32,7 @@ dynamic = ["version"]
 dependencies = [
     "fastapi",
     "fmu-datamodels",
-    "fmu-settings>=0.26.0",
+    "fmu-settings>=0.28.0",
     "httpx",
     "packaging",
     "pydantic",

src/fmu_settings_api/v1/routes/project.py

@@ -15,6 +15,10 @@
 from fmu.datamodels.fmu_results.fields import Model
 from fmu.settings import CacheResource, ProjectFMUDirectory
 from fmu.settings._global_config import InvalidGlobalConfigurationError
+from fmu.settings._init import (
+    REQUIRED_FMU_PROJECT_SUBDIRS,
+    InvalidFMUProjectPathError,
+)
 from fmu.settings.models.change_info import ChangeInfo
 from fmu.settings.models.diff import ResourceDiff
 from fmu.settings.models.log import Log
@@ -60,6 +64,9 @@
 )
 
 router = APIRouter(prefix="/project", tags=["project"])
+REQUIRED_PROJECT_DIRS_TEXT = ", ".join(
+    f"'{dir_name}'" for dir_name in REQUIRED_FMU_PROJECT_SUBDIRS
+)
 
 ProjectResponses: Final[Responses] = {
     **inline_add_response(
@@ -104,6 +111,24 @@
     ),
 }
 
+ProjectInitResponses: Final[Responses] = {
+    **ProjectResponses,
+    **ProjectExistsResponses,
+    **inline_add_response(
+        422,
+        "The requested path exists but is not a valid FMU project root.",
+        [
+            {
+                "detail": (
+                    "Failed initializing .fmu directory. Initialize it from a "
+                    f"project root containing {REQUIRED_PROJECT_DIRS_TEXT}. "
+                    "Did not find: {missing_project_dirs}."
+                ),
+            },
+        ],
+    ),
+}
+
 LockConflictResponses: Final[Responses] = {
     **inline_add_response(
         423,
@@ -481,8 +506,7 @@ async def post_project(
     ),
     responses={
         **GetSessionResponses,
-        **ProjectResponses,
-        **ProjectExistsResponses,
+        **ProjectInitResponses,
     },
 )
 async def post_init_project(
@@ -504,6 +528,8 @@ async def post_init_project(
         raise HTTPException(
             status_code=404, detail=f"Path {path} does not exist"
         ) from e
+    except InvalidFMUProjectPathError as e:
+        raise HTTPException(status_code=422, detail=str(e)) from e
     except FileExistsError as e:
         raise HTTPException(
             status_code=409, detail=f".fmu already exists at {path}"

tests/conftest.py

@@ -19,7 +19,11 @@
 )
 from fmu.settings import ProjectFMUDirectory
 from fmu.settings._fmu_dir import UserFMUDirectory
-from fmu.settings._init import init_fmu_directory, init_user_fmu_directory
+from fmu.settings._init import (
+    REQUIRED_FMU_PROJECT_SUBDIRS,
+    init_fmu_directory,
+    init_user_fmu_directory,
+)
 from pytest import MonkeyPatch
 
 from fmu_settings_api.__main__ import app
@@ -29,6 +33,31 @@
 from fmu_settings_api.session import SessionManager, add_fmu_project_to_session
 
 
+@pytest.fixture
+def make_fmu_project_root() -> Callable[[Path], Path]:
+    """Return a helper that prepares a valid FMU project root for a test path."""
+
+    def _make_fmu_project_root(path: Path) -> Path:
+        path.mkdir(parents=True, exist_ok=True)
+        for dir_name in REQUIRED_FMU_PROJECT_SUBDIRS:
+            (path / dir_name).mkdir(parents=True, exist_ok=True)
+        return path
+
+    return _make_fmu_project_root
+
+
+@pytest.fixture
+def init_project_fmu_directory(
+    make_fmu_project_root: Callable[[Path], Path],
+) -> Callable[[Path], ProjectFMUDirectory]:
+    """Return a helper that initializes a valid project .fmu directory."""
+
+    def _init_project_fmu_directory(path: Path) -> ProjectFMUDirectory:
+        return init_fmu_directory(make_fmu_project_root(path))
+
+    return _init_project_fmu_directory
+
+
 @pytest.fixture
 def create_stratigraphic_unit() -> Callable[..., StratigraphicUnit]:
     """Fixture that returns a helper function to create StratigraphicUnit.
@@ -153,9 +182,11 @@ def mock_token() -> str:
 
 
 @pytest.fixture
-def fmu_dir(tmp_path: Path) -> ProjectFMUDirectory:
+def fmu_dir(
+    tmp_path: Path, make_fmu_project_root: Callable[[Path], Path]
+) -> ProjectFMUDirectory:
     """Creates a .fmu directory in a tmp path."""
-    return init_fmu_directory(tmp_path)
+    return init_fmu_directory(make_fmu_project_root(tmp_path))
 
 
 @pytest.fixture
@@ -193,7 +224,11 @@ def user_fmu_dir_no_permissions(fmu_dir_path: Path) -> Generator[Path]:
 
 
 @pytest.fixture
-def tmp_path_mocked_home(tmp_path: Path, monkeypatch: MonkeyPatch) -> Generator[Path]:
+def tmp_path_mocked_home(
+    tmp_path: Path,
+    monkeypatch: MonkeyPatch,
+    make_fmu_project_root: Callable[[Path], Path],
+) -> Generator[Path]:
     """Mocks Path.home() for routes that depend on UserFMUDirectory.
 
     This mocks the user .fmu into tmp_path/home/.fmu.
@@ -203,6 +238,7 @@ def tmp_path_mocked_home(tmp_path: Path, monkeypatch: MonkeyPatch) -> Generator[
     """
     mocked_user_home = tmp_path / "home"
     mocked_user_home.mkdir()
+    make_fmu_project_root(tmp_path)
     with patch("pathlib.Path.home", return_value=mocked_user_home):
         monkeypatch.chdir(tmp_path)
         yield tmp_path