core/stats: get rid of duplicated keys for 'auto stats'

previously:
```
{'iter_data': {'iter_data': {'count': 9, 'last': datetime.datetime(2020, 1, 3, 1, 1, 1)}}}
```

after
```
{'iter_data': {'count': 9, 'last': datetime.datetime(2020, 1, 3, 1, 1, 1)}}
```

my/core/common.py

@@ -401,7 +401,12 @@ C = TypeVar('C')
 Stats = Dict[str, Any]
 StatsFun = Callable[[], Stats]
 # todo not sure about return type...
-def stat(func: Union[Callable[[], Iterable[C]], Iterable[C]], quick: bool=False) -> Stats:
+def stat(
+    func: Union[Callable[[], Iterable[C]], Iterable[C]],
+    *,
+    quick: bool = False,
+    name: Optional[str] = None,
+) -> Stats:
     if callable(func):
         fr = func()
         fname = func.__name__
@@ -409,8 +414,8 @@ def stat(func: Union[Callable[[], Iterable[C]], Iterable[C]], quick: bool=False)
         # meh. means it's just a list.. not sure how to generate a name then
         fr = func
         fname = f'unnamed_{id(fr)}'
-    tname = type(fr).__name__
-    if tname == 'DataFrame':
+    type_name = type(fr).__name__
+    if type_name == 'DataFrame':
         # dynamic, because pandas is an optional dependency..
         df = cast(Any, fr)  # todo ugh, not sure how to annotate properly
         res = dict(
@@ -419,8 +424,10 @@ def stat(func: Union[Callable[[], Iterable[C]], Iterable[C]], quick: bool=False)
         )
     else:
         res = _stat_iterable(fr, quick=quick)
+
+    stat_name = name if name is not None else fname
     return {
-        fname: res,
+        stat_name: res,
     }
 
 

my/core/stats.py

@@ -12,16 +12,35 @@ from .common import StatsFun, Stats, stat
 
 # TODO maybe could be enough to annotate OUTPUTS or something like that?
 # then stats could just use them as hints?
-def guess_stats(module_name: str, quick: bool=False) -> Optional[StatsFun]:
+def guess_stats(module_name: str, quick: bool = False) -> Optional[StatsFun]:
     providers = guess_data_providers(module_name)
     if len(providers) == 0:
         return None
 
     def auto_stats() -> Stats:
-        return {k: stat(v, quick=quick) for k, v in providers.items()}
+        res = {}
+        for k, v in providers.items():
+            res.update(stat(v, quick=quick, name=k))
+        return res
+
     return auto_stats
 
 
+def test_guess_stats() -> None:
+    from datetime import datetime
+    import my.core.tests.auto_stats as M
+
+    auto_stats = guess_stats(M.__name__)
+    res = auto_stats()
+    assert res.keys() == {'iter_data'}
+
+    r = res['iter_data']
+    assert r == {
+        'count': 9,
+        'last': datetime(2020, 1, 3, 1, 1, 1),
+    }
+
+
 def guess_data_providers(module_name: str) -> Dict[str, Callable]:
     module = importlib.import_module(module_name)
     mfunctions = inspect.getmembers(module, inspect.isfunction)

my/core/tests/auto_stats.py

@@ -0,0 +1,30 @@
+"""
+Helper 'module' for test_guess_stats
+"""
+
+from dataclasses import dataclass
+from datetime import datetime, timedelta
+from pathlib import Path
+from typing import Iterable, Sequence
+
+
+@dataclass
+class Item:
+    id: str
+    dt: datetime
+    source: Path
+
+
+def inputs() -> Sequence[Path]:
+    return [
+        Path('file1.json'),
+        Path('file2.json'),
+        Path('file3.json'),
+    ]
+
+
+def iter_data() -> Iterable[Item]:
+    dt = datetime.fromisoformat('2020-01-01 01:01:01')
+    for path in inputs():
+        for i in range(3):
+            yield Item(id=str(i), dt=dt + timedelta(days=i), source=path)