feat: add search to crud paginate function (#17)

* feat: add search to crud paginate function

* fixes: comments + tests import

.github/workflows/build-release.yml

@@ -17,7 +17,7 @@ jobs:
         uses: astral-sh/setup-uv@v7
 
       - name: Set up Python
-        run: uv python install 3.13
+        run: uv python install 3.14
 
       - name: Install dependencies
         run: uv sync

.github/workflows/ci.yml

@@ -56,7 +56,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.11", "3.12", "3.13", "3.14"]
 
     services:
       postgres:
@@ -92,7 +92,7 @@ jobs:
           uv run pytest --cov --cov-report=xml --cov-report=term-missing
 
       - name: Upload coverage to Codecov
-        if: matrix.python-version == '3.13'
+        if: matrix.python-version == '3.14'
         uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}

.python-version

@@ -1 +1 @@
-3.13
+3.14

pyproject.toml

@@ -24,6 +24,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: Software Development :: Libraries",
     "Topic :: Software Development",

src/fastapi_toolsets/crud/__init__.py

@@ -0,0 +1,17 @@
+"""Generic async CRUD operations for SQLAlchemy models."""
+
+from ..exceptions import NoSearchableFieldsError
+from .factory import CrudFactory
+from .search import (
+    SearchConfig,
+    SearchFieldType,
+    get_searchable_fields,
+)
+
+__all__ = [
+    "CrudFactory",
+    "get_searchable_fields",
+    "NoSearchableFieldsError",
+    "SearchConfig",
+    "SearchFieldType",
+]

src/fastapi_toolsets/crud/factory.py

@@ -12,13 +12,9 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import DeclarativeBase
 from sqlalchemy.sql.roles import WhereHavingRole
 
-from .db import get_transaction
-from .exceptions import NotFoundError
-
-__all__ = [
-    "AsyncCrud",
-    "CrudFactory",
-]
+from ..db import get_transaction
+from ..exceptions import NotFoundError
+from .search import SearchConfig, SearchFieldType, build_search_filters
 
 ModelType = TypeVar("ModelType", bound=DeclarativeBase)
 
@@ -27,20 +23,10 @@ class AsyncCrud(Generic[ModelType]):
     """Generic async CRUD operations for SQLAlchemy models.
 
     Subclass this and set the `model` class variable, or use `CrudFactory`.
-
-    Example:
-        class UserCrud(AsyncCrud[User]):
-            model = User
-
-        # Or use the factory:
-        UserCrud = CrudFactory(User)
-
-        # Then use it:
-        user = await UserCrud.get(session, [User.id == 1])
-        users = await UserCrud.get_multi(session, limit=10)
     """
 
     model: ClassVar[type[DeclarativeBase]]
+    searchable_fields: ClassVar[Sequence[SearchFieldType] | None] = None
 
     @classmethod
     async def create(
@@ -313,6 +299,8 @@ class AsyncCrud(Generic[ModelType]):
         order_by: Any | None = None,
         page: int = 1,
         items_per_page: int = 20,
+        search: str | SearchConfig | None = None,
+        search_fields: Sequence[SearchFieldType] | None = None,
     ) -> dict[str, Any]:
         """Get paginated results with metadata.
 
@@ -323,23 +311,54 @@ class AsyncCrud(Generic[ModelType]):
             order_by: Column or list of columns to order by
             page: Page number (1-indexed)
             items_per_page: Number of items per page
+            search: Search query string or SearchConfig object
+            search_fields: Fields to search in (overrides class default)
 
         Returns:
             Dict with 'data' and 'pagination' keys
         """
-        filters = filters or []
+        filters = list(filters) if filters else []
         offset = (page - 1) * items_per_page
+        joins: list[Any] = []
 
-        items = await cls.get_multi(
-            session,
-            filters=filters,
-            load_options=load_options,
-            order_by=order_by,
-            limit=items_per_page,
-            offset=offset,
-        )
+        # Build search filters
+        if search:
+            search_filters, search_joins = build_search_filters(
+                cls.model,
+                search,
+                search_fields=search_fields,
+                default_fields=cls.searchable_fields,
+            )
+            filters.extend(search_filters)
+            joins.extend(search_joins)
 
-        total_count = await cls.count(session, filters=filters)
+        # Build query with joins
+        q = select(cls.model)
+        for join_rel in joins:
+            q = q.outerjoin(join_rel)
+
+        if filters:
+            q = q.where(and_(*filters))
+        if load_options:
+            q = q.options(*load_options)
+        if order_by is not None:
+            q = q.order_by(order_by)
+
+        q = q.offset(offset).limit(items_per_page)
+        result = await session.execute(q)
+        items = result.unique().scalars().all()
+
+        # Count query (with same joins and filters)
+        pk_col = cls.model.__mapper__.primary_key[0]
+        count_q = select(func.count(func.distinct(getattr(cls.model, pk_col.name))))
+        count_q = count_q.select_from(cls.model)
+        for join_rel in joins:
+            count_q = count_q.outerjoin(join_rel)
+        if filters:
+            count_q = count_q.where(and_(*filters))
+
+        count_result = await session.execute(count_q)
+        total_count = count_result.scalar_one()
 
         return {
             "data": items,
@@ -354,11 +373,14 @@ class AsyncCrud(Generic[ModelType]):
 
 def CrudFactory(
     model: type[ModelType],
+    *,
+    searchable_fields: Sequence[SearchFieldType] | None = None,
 ) -> type[AsyncCrud[ModelType]]:
     """Create a CRUD class for a specific model.
 
     Args:
         model: SQLAlchemy model class
+        searchable_fields: Optional list of searchable fields
 
     Returns:
         AsyncCrud subclass bound to the model
@@ -370,9 +392,25 @@ def CrudFactory(
         UserCrud = CrudFactory(User)
         PostCrud = CrudFactory(Post)
 
+        # With searchable fields:
+        UserCrud = CrudFactory(
+            User,
+            searchable_fields=[User.username, User.email, (User.role, Role.name)]
+        )
+
         # Usage
         user = await UserCrud.get(session, [User.id == 1])
         posts = await PostCrud.get_multi(session, filters=[Post.user_id == user.id])
+
+        # With search
+        result = await UserCrud.paginate(session, search="john")
     """
-    cls = type(f"Async{model.__name__}Crud", (AsyncCrud,), {"model": model})
+    cls = type(
+        f"Async{model.__name__}Crud",
+        (AsyncCrud,),
+        {
+            "model": model,
+            "searchable_fields": searchable_fields,
+        },
+    )
     return cast(type[AsyncCrud[ModelType]], cls)

src/fastapi_toolsets/crud/search.py

@@ -0,0 +1,145 @@
+"""Search utilities for AsyncCrud."""
+
+from collections.abc import Sequence
+from dataclasses import dataclass
+from typing import TYPE_CHECKING, Any, Literal
+
+from sqlalchemy import String, or_
+from sqlalchemy.orm import DeclarativeBase
+from sqlalchemy.orm.attributes import InstrumentedAttribute
+
+from ..exceptions import NoSearchableFieldsError
+
+if TYPE_CHECKING:
+    from sqlalchemy.sql.elements import ColumnElement
+
+SearchFieldType = InstrumentedAttribute[Any] | tuple[InstrumentedAttribute[Any], ...]
+
+
+@dataclass
+class SearchConfig:
+    """Advanced search configuration.
+
+    Attributes:
+        query: The search string
+        fields: Fields to search (columns or tuples for relationships)
+        case_sensitive: Case-sensitive search (default: False)
+        match_mode: "any" (OR) or "all" (AND) to combine fields
+    """
+
+    query: str
+    fields: Sequence[SearchFieldType] | None = None
+    case_sensitive: bool = False
+    match_mode: Literal["any", "all"] = "any"
+
+
+def get_searchable_fields(
+    model: type[DeclarativeBase],
+    *,
+    include_relationships: bool = True,
+    max_depth: int = 1,
+) -> list[SearchFieldType]:
+    """Auto-detect String fields on a model and its relationships.
+
+    Args:
+        model: SQLAlchemy model class
+        include_relationships: Include fields from many-to-one/one-to-one relationships
+        max_depth: Max depth for relationship traversal (default: 1)
+
+    Returns:
+        List of columns and tuples (relationship, column)
+    """
+    fields: list[SearchFieldType] = []
+    mapper = model.__mapper__
+
+    # Direct String columns
+    for col in mapper.columns:
+        if isinstance(col.type, String):
+            fields.append(getattr(model, col.key))
+
+    # Relationships (one-to-one, many-to-one only)
+    if include_relationships and max_depth > 0:
+        for rel_name, rel_prop in mapper.relationships.items():
+            if rel_prop.uselist:  # Skip collections (one-to-many, many-to-many)
+                continue
+
+            rel_attr = getattr(model, rel_name)
+            related_model = rel_prop.mapper.class_
+
+            for col in related_model.__mapper__.columns:
+                if isinstance(col.type, String):
+                    fields.append((rel_attr, getattr(related_model, col.key)))
+
+    return fields
+
+
+def build_search_filters(
+    model: type[DeclarativeBase],
+    search: str | SearchConfig,
+    search_fields: Sequence[SearchFieldType] | None = None,
+    default_fields: Sequence[SearchFieldType] | None = None,
+) -> tuple[list["ColumnElement[bool]"], list[InstrumentedAttribute[Any]]]:
+    """Build SQLAlchemy filter conditions for search.
+
+    Args:
+        model: SQLAlchemy model class
+        search: Search string or SearchConfig
+        search_fields: Fields specified per-call (takes priority)
+        default_fields: Default fields (from ClassVar)
+
+    Returns:
+        Tuple of (filter_conditions, joins_needed)
+    """
+    # Normalize input
+    if isinstance(search, str):
+        config = SearchConfig(query=search, fields=search_fields)
+    else:
+        config = search
+        if search_fields is not None:
+            config = SearchConfig(
+                query=config.query,
+                fields=search_fields,
+                case_sensitive=config.case_sensitive,
+                match_mode=config.match_mode,
+            )
+
+    if not config.query or not config.query.strip():
+        return [], []
+
+    # Determine which fields to search
+    fields = config.fields or default_fields or get_searchable_fields(model)
+
+    if not fields:
+        raise NoSearchableFieldsError(model)
+
+    query = config.query.strip()
+    filters: list[ColumnElement[bool]] = []
+    joins: list[InstrumentedAttribute[Any]] = []
+    added_joins: set[str] = set()
+
+    for field in fields:
+        if isinstance(field, tuple):
+            # Relationship: (User.role, Role.name) or deeper
+            for rel in field[:-1]:
+                rel_key = str(rel)
+                if rel_key not in added_joins:
+                    joins.append(rel)
+                    added_joins.add(rel_key)
+            column = field[-1]
+        else:
+            column = field
+
+        # Build the filter
+        if config.case_sensitive:
+            filters.append(column.like(f"%{query}%"))
+        else:
+            filters.append(column.ilike(f"%{query}%"))
+
+    if not filters:
+        return [], []
+
+    # Combine based on match_mode
+    if config.match_mode == "any":
+        return [or_(*filters)], joins
+    else:
+        return filters, joins

src/fastapi_toolsets/exceptions/__init__.py

@@ -2,6 +2,7 @@ from .exceptions import (
     ApiException,
     ConflictError,
     ForbiddenError,
+    NoSearchableFieldsError,
     NotFoundError,
     UnauthorizedError,
     generate_error_responses,
@@ -14,6 +15,7 @@ __all__ = [
     "ApiException",
     "ConflictError",
     "ForbiddenError",
+    "NoSearchableFieldsError",
     "NotFoundError",
     "UnauthorizedError",
 ]

src/fastapi_toolsets/exceptions/exceptions.py

@@ -119,6 +119,25 @@ class RoleNotFoundError(NotFoundError):
     )
 
 
+class NoSearchableFieldsError(ApiException):
+    """Raised when search is requested but no searchable fields are available."""
+
+    api_error = ApiError(
+        code=400,
+        msg="No Searchable Fields",
+        desc="No searchable fields configured for this resource.",
+        err_code="SEARCH-400",
+    )
+
+    def __init__(self, model: type) -> None:
+        self.model = model
+        detail = (
+            f"No searchable fields found for model '{model.__name__}'. "
+            "Provide 'search_fields' parameter or set 'searchable_fields' on the CRUD class."
+        )
+        super().__init__(detail)
+
+
 def generate_error_responses(
     *errors: type[ApiException],
 ) -> dict[int | str, dict[str, Any]]:

tests/test_crud.py

@@ -3,7 +3,8 @@
 import pytest
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from fastapi_toolsets.crud import AsyncCrud, CrudFactory
+from fastapi_toolsets.crud import CrudFactory
+from fastapi_toolsets.crud.factory import AsyncCrud
 from fastapi_toolsets.exceptions import NotFoundError
 
 from .conftest import (

tests/test_crud_search.py

@@ -0,0 +1,392 @@
+"""Tests for CRUD search functionality."""
+
+import pytest
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from fastapi_toolsets.crud import SearchConfig, get_searchable_fields
+
+from .conftest import (
+    Role,
+    RoleCreate,
+    RoleCrud,
+    User,
+    UserCreate,
+    UserCrud,
+)
+
+
+class TestPaginateSearch:
+    """Tests for paginate() with search."""
+
+    @pytest.mark.anyio
+    async def test_search_single_column(self, db_session: AsyncSession):
+        """Search on a single direct column."""
+        await UserCrud.create(
+            db_session, UserCreate(username="john_doe", email="john@test.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="jane_doe", email="jane@test.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="bob_smith", email="bob@test.com")
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="doe",
+            search_fields=[User.username],
+        )
+
+        assert result["pagination"]["total_count"] == 2
+
+    @pytest.mark.anyio
+    async def test_search_multiple_columns(self, db_session: AsyncSession):
+        """Search across multiple columns (OR logic)."""
+        await UserCrud.create(
+            db_session, UserCreate(username="alice", email="alice@company.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="company_bob", email="bob@other.com")
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="company",
+            search_fields=[User.username, User.email],
+        )
+
+        assert result["pagination"]["total_count"] == 2
+
+    @pytest.mark.anyio
+    async def test_search_relationship_depth1(self, db_session: AsyncSession):
+        """Search through a relationship (depth 1)."""
+        admin_role = await RoleCrud.create(db_session, RoleCreate(name="administrator"))
+        user_role = await RoleCrud.create(db_session, RoleCreate(name="basic_user"))
+
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="admin1", email="a1@test.com", role_id=admin_role.id),
+        )
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="admin2", email="a2@test.com", role_id=admin_role.id),
+        )
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="user1", email="u1@test.com", role_id=user_role.id),
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="admin",
+            search_fields=[(User.role, Role.name)],
+        )
+
+        assert result["pagination"]["total_count"] == 2
+
+    @pytest.mark.anyio
+    async def test_search_mixed_direct_and_relation(self, db_session: AsyncSession):
+        """Search combining direct columns and relationships."""
+        role = await RoleCrud.create(db_session, RoleCreate(name="admin"))
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="john", email="john@test.com", role_id=role.id),
+        )
+
+        # Search "admin" in username OR role.name
+        result = await UserCrud.paginate(
+            db_session,
+            search="admin",
+            search_fields=[User.username, (User.role, Role.name)],
+        )
+
+        assert result["pagination"]["total_count"] == 1
+
+    @pytest.mark.anyio
+    async def test_search_case_insensitive(self, db_session: AsyncSession):
+        """Search is case-insensitive by default."""
+        await UserCrud.create(
+            db_session, UserCreate(username="JohnDoe", email="j@test.com")
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="johndoe",
+            search_fields=[User.username],
+        )
+
+        assert result["pagination"]["total_count"] == 1
+
+    @pytest.mark.anyio
+    async def test_search_case_sensitive(self, db_session: AsyncSession):
+        """Case-sensitive search with SearchConfig."""
+        await UserCrud.create(
+            db_session, UserCreate(username="JohnDoe", email="j@test.com")
+        )
+
+        # Should not find (case mismatch)
+        result = await UserCrud.paginate(
+            db_session,
+            search=SearchConfig(query="johndoe", case_sensitive=True),
+            search_fields=[User.username],
+        )
+        assert result["pagination"]["total_count"] == 0
+
+        # Should find (case match)
+        result = await UserCrud.paginate(
+            db_session,
+            search=SearchConfig(query="JohnDoe", case_sensitive=True),
+            search_fields=[User.username],
+        )
+        assert result["pagination"]["total_count"] == 1
+
+    @pytest.mark.anyio
+    async def test_search_empty_query(self, db_session: AsyncSession):
+        """Empty search returns all results."""
+        await UserCrud.create(
+            db_session, UserCreate(username="user1", email="u1@test.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="user2", email="u2@test.com")
+        )
+
+        result = await UserCrud.paginate(db_session, search="")
+        assert result["pagination"]["total_count"] == 2
+
+        result = await UserCrud.paginate(db_session, search=None)
+        assert result["pagination"]["total_count"] == 2
+
+    @pytest.mark.anyio
+    async def test_search_with_existing_filters(self, db_session: AsyncSession):
+        """Search combines with existing filters (AND)."""
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="active_john", email="aj@test.com", is_active=True),
+        )
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="inactive_john", email="ij@test.com", is_active=False),
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            filters=[User.is_active == True],  # noqa: E712
+            search="john",
+            search_fields=[User.username],
+        )
+
+        assert result["pagination"]["total_count"] == 1
+        assert result["data"][0].username == "active_john"
+
+    @pytest.mark.anyio
+    async def test_search_auto_detect_fields(self, db_session: AsyncSession):
+        """Auto-detect searchable fields when not specified."""
+        await UserCrud.create(
+            db_session, UserCreate(username="findme", email="other@test.com")
+        )
+
+        result = await UserCrud.paginate(db_session, search="findme")
+
+        assert result["pagination"]["total_count"] == 1
+
+    @pytest.mark.anyio
+    async def test_search_no_results(self, db_session: AsyncSession):
+        """Search with no matching results."""
+        await UserCrud.create(
+            db_session, UserCreate(username="john", email="j@test.com")
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="nonexistent",
+            search_fields=[User.username],
+        )
+
+        assert result["pagination"]["total_count"] == 0
+        assert result["data"] == []
+
+    @pytest.mark.anyio
+    async def test_search_with_pagination(self, db_session: AsyncSession):
+        """Search respects pagination parameters."""
+        for i in range(15):
+            await UserCrud.create(
+                db_session,
+                UserCreate(username=f"user_{i}", email=f"user{i}@test.com"),
+            )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="user_",
+            search_fields=[User.username],
+            page=1,
+            items_per_page=5,
+        )
+
+        assert result["pagination"]["total_count"] == 15
+        assert len(result["data"]) == 5
+        assert result["pagination"]["has_more"] is True
+
+    @pytest.mark.anyio
+    async def test_search_null_relationship(self, db_session: AsyncSession):
+        """Users without relationship are included (outerjoin)."""
+        role = await RoleCrud.create(db_session, RoleCreate(name="admin"))
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="with_role", email="wr@test.com", role_id=role.id),
+        )
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="no_role", email="nr@test.com", role_id=None),
+        )
+
+        # Search in username, not in role
+        result = await UserCrud.paginate(
+            db_session,
+            search="role",
+            search_fields=[User.username],
+        )
+
+        assert result["pagination"]["total_count"] == 2
+
+    @pytest.mark.anyio
+    async def test_search_with_order_by(self, db_session: AsyncSession):
+        """Search works with order_by parameter."""
+        await UserCrud.create(
+            db_session, UserCreate(username="charlie", email="c@test.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="alice", email="a@test.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="bob", email="b@test.com")
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search="@test.com",
+            search_fields=[User.email],
+            order_by=User.username,
+        )
+
+        assert result["pagination"]["total_count"] == 3
+        usernames = [u.username for u in result["data"]]
+        assert usernames == ["alice", "bob", "charlie"]
+
+
+class TestSearchConfig:
+    """Tests for SearchConfig options."""
+
+    @pytest.mark.anyio
+    async def test_match_mode_all(self, db_session: AsyncSession):
+        """match_mode='all' requires all fields to match (AND)."""
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="john_test", email="john_test@company.com"),
+        )
+        await UserCrud.create(
+            db_session,
+            UserCreate(username="john_other", email="other@example.com"),
+        )
+
+        # 'john' must be in username AND email
+        result = await UserCrud.paginate(
+            db_session,
+            search=SearchConfig(query="john", match_mode="all"),
+            search_fields=[User.username, User.email],
+        )
+
+        assert result["pagination"]["total_count"] == 1
+        assert result["data"][0].username == "john_test"
+
+    @pytest.mark.anyio
+    async def test_search_config_with_fields(self, db_session: AsyncSession):
+        """SearchConfig can specify fields directly."""
+        await UserCrud.create(
+            db_session, UserCreate(username="test", email="findme@test.com")
+        )
+
+        result = await UserCrud.paginate(
+            db_session,
+            search=SearchConfig(query="findme", fields=[User.email]),
+        )
+
+        assert result["pagination"]["total_count"] == 1
+
+
+class TestNoSearchableFieldsError:
+    """Tests for NoSearchableFieldsError exception."""
+
+    def test_error_is_api_exception(self):
+        """NoSearchableFieldsError inherits from ApiException."""
+        from fastapi_toolsets.exceptions import ApiException, NoSearchableFieldsError
+
+        assert issubclass(NoSearchableFieldsError, ApiException)
+
+    def test_error_has_api_error_fields(self):
+        """NoSearchableFieldsError has proper api_error configuration."""
+        from fastapi_toolsets.exceptions import NoSearchableFieldsError
+
+        assert NoSearchableFieldsError.api_error.code == 400
+        assert NoSearchableFieldsError.api_error.err_code == "SEARCH-400"
+
+    def test_error_message_contains_model_name(self):
+        """Error message includes the model name."""
+        from fastapi_toolsets.exceptions import NoSearchableFieldsError
+
+        error = NoSearchableFieldsError(User)
+        assert "User" in str(error)
+        assert error.model is User
+
+    def test_error_raised_when_no_fields(self):
+        """Error is raised when search has no searchable fields."""
+        from sqlalchemy import Integer
+        from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+        from fastapi_toolsets.crud.search import build_search_filters
+        from fastapi_toolsets.exceptions import NoSearchableFieldsError
+
+        # Model with no String columns
+        class NoStringBase(DeclarativeBase):
+            pass
+
+        class NoStringModel(NoStringBase):
+            __tablename__ = "no_strings"
+            id: Mapped[int] = mapped_column(Integer, primary_key=True)
+            count: Mapped[int] = mapped_column(Integer, default=0)
+
+        with pytest.raises(NoSearchableFieldsError) as exc_info:
+            build_search_filters(NoStringModel, "test")
+
+        assert exc_info.value.model is NoStringModel
+        assert "NoStringModel" in str(exc_info.value)
+
+
+class TestGetSearchableFields:
+    """Tests for auto-detection of searchable fields."""
+
+    def test_detects_string_columns(self):
+        """Detects String columns on the model."""
+        fields = get_searchable_fields(User, include_relationships=False)
+
+        # Should include username and email (String), not id or is_active
+        field_names = [str(f) for f in fields]
+        assert any("username" in f for f in field_names)
+        assert any("email" in f for f in field_names)
+        assert not any("id" in f and "role_id" not in f for f in field_names)
+        assert not any("is_active" in f for f in field_names)
+
+    def test_detects_relationship_fields(self):
+        """Detects String fields on related models."""
+        fields = get_searchable_fields(User, include_relationships=True)
+
+        # Should include (User.role, Role.name)
+        has_role_name = any(isinstance(f, tuple) and len(f) == 2 for f in fields)
+        assert has_role_name
+
+    def test_skips_collection_relationships(self):
+        """Skips one-to-many relationships."""
+        fields = get_searchable_fields(Role, include_relationships=True)
+
+        # Role.users is a collection, should not be included
+        field_strs = [str(f) for f in fields]
+        assert not any("users" in f for f in field_strs)