Type repr, cursor __all__, dead-assert removal

- Give _DBAPIType singletons readable repr (STRING, BINARY, NUMBER,
  DATETIME, ROWID) via a _name keyword on __init__. Improves pytest
  parametrize ids, log output, and debugging.
- Remove dead `assert offset is not None` in _iso8601_from_datetime;
  replace with a defensive `if offset is None: return base` that
  both satisfies mypy type narrowing and survives python -O. The
  branch is unreachable from valid Python tzinfo subclasses but
  keeps the formatter robust to pathological tzinfo.
- Add explicit `__all__ = ["Cursor"]` to cursor module so `from
  dqlitedbapi.cursor import *` no longer leaks private helpers
  (_call_client, _convert_row, etc.). Matches the pattern already
  established in aio/cursor.py.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqlitedbapi/cursor.py

@@ -21,6 +21,8 @@
 )
 from dqlitewire.constants import ValueType
 
+__all__ = ["Cursor"]
+
 
 async def _call_client(coro: Coroutine[Any, Any, Any]) -> Any:
     """Await a client-layer coroutine, mapping its exceptions into the

src/dqlitedbapi/types.py

@@ -61,14 +61,15 @@ class _DBAPIType:
     (int).
     """
 
-    def __init__(self, *values: str | int | ValueType) -> None:
+    def __init__(self, *values: str | int | ValueType, _name: str = "") -> None:
         normalized: set[str | int] = set()
         for v in values:
             if isinstance(v, ValueType):
                 normalized.add(int(v))
             else:
                 normalized.add(v)
         self.values = normalized
+        self._name = _name
 
     def __eq__(self, other: object) -> bool:
         if isinstance(other, str):
@@ -82,9 +83,12 @@ def __eq__(self, other: object) -> bool:
     def __hash__(self) -> int:
         return hash(frozenset(self.values))
 
+    def __repr__(self) -> str:
+        return self._name or f"_DBAPIType({sorted(self.values, key=str)!r})"
 
-STRING = _DBAPIType("TEXT", "VARCHAR", "CHAR", "CLOB", ValueType.TEXT)
-BINARY = _DBAPIType("BLOB", "BINARY", "VARBINARY", ValueType.BLOB)
+
+STRING = _DBAPIType("TEXT", "VARCHAR", "CHAR", "CLOB", ValueType.TEXT, _name="STRING")
+BINARY = _DBAPIType("BLOB", "BINARY", "VARBINARY", ValueType.BLOB, _name="BINARY")
 NUMBER = _DBAPIType(
     "INTEGER",
     "INT",
@@ -97,6 +101,7 @@ def __hash__(self) -> int:
     ValueType.INTEGER,
     ValueType.FLOAT,
     ValueType.BOOLEAN,
+    _name="NUMBER",
 )
 DATETIME = _DBAPIType(
     "DATE",
@@ -105,8 +110,9 @@ def __hash__(self) -> int:
     "DATETIME",
     ValueType.ISO8601,
     ValueType.UNIXTIME,
+    _name="DATETIME",
 )
-ROWID = _DBAPIType("ROWID", "INTEGER PRIMARY KEY", ValueType.INTEGER)
+ROWID = _DBAPIType("ROWID", "INTEGER PRIMARY KEY", ValueType.INTEGER, _name="ROWID")
 
 
 # Internal conversion helpers.
@@ -132,8 +138,11 @@ def _iso8601_from_datetime(value: datetime.datetime | datetime.date) -> str:
             base += f".{value.microsecond:06d}"
         if value.tzinfo is None:
             return base
+        # tzinfo is set (checked above), so utcoffset() returns timedelta.
+        # A None here would indicate a broken tzinfo subclass; be explicit.
         offset = value.utcoffset()
-        assert offset is not None
+        if offset is None:
+            return base
         total_seconds = int(offset.total_seconds())
         sign = "+" if total_seconds >= 0 else "-"
         hours, remainder = divmod(abs(total_seconds), 3600)

tests/test_module_attributes.py

@@ -90,3 +90,26 @@ def test_datetime_type(self) -> None:
 
     def test_rowid_type(self) -> None:
         assert dqlitedbapi.ROWID == "ROWID"
+
+
+class TestDBAPITypeRepr:
+    def test_named_types_have_readable_repr(self) -> None:
+        assert repr(dqlitedbapi.STRING) == "STRING"
+        assert repr(dqlitedbapi.BINARY) == "BINARY"
+        assert repr(dqlitedbapi.NUMBER) == "NUMBER"
+        assert repr(dqlitedbapi.DATETIME) == "DATETIME"
+        assert repr(dqlitedbapi.ROWID) == "ROWID"
+
+
+class TestCursorModuleAll:
+    def test_cursor_module_has_all(self) -> None:
+        from dqlitedbapi import cursor as cursor_mod
+
+        assert cursor_mod.__all__ == ["Cursor"]
+
+    def test_cursor_module_wildcard_import_does_not_leak_helpers(self) -> None:
+        from dqlitedbapi import cursor as cursor_mod
+
+        # Verify private helpers exist on the module but are not in __all__.
+        assert hasattr(cursor_mod, "_call_client")
+        assert "_call_client" not in cursor_mod.__all__