Inject state class into setUp and tearDown tasks

of the Benchmark class. This is necessary such that the setUp and
tearDown tasks know the benchmark states. Namely, how many bench-
marks are in the benchmark family and the index of the current.

In a follow up implementation of a cache we will use the index
and family lenght to compute a condition to empty the cache.

src/nnbench/core.py

@@ -9,7 +9,7 @@
 import warnings
 from typing import Any, Callable, Iterable, Union, get_args, get_origin, overload
 
-from nnbench.types import Benchmark
+from nnbench.types import Benchmark, State
 from nnbench.types.util import is_memo, is_memo_type
 
 
@@ -167,7 +167,7 @@ def parametrize(
     def decorator(fn: Callable) -> list[Benchmark]:
         benchmarks = []
         names = set()
-        for params in parameters:
+        for idx, params in enumerate(parameters):
             _check_against_interface(params, fn)
 
             name = namegen(fn, **params)
@@ -177,8 +177,23 @@ def decorator(fn: Callable) -> list[Benchmark]:
                     f"Perhaps you specified a parameter configuration twice?"
                 )
             names.add(name)
+            state = State(
+                name=name,
+                function=fn,
+                family=fn.__name__,
+                family_size=len(list(parameters)),
+                family_index=idx,
+            )
 
-            bm = Benchmark(fn, name=name, params=params, setUp=setUp, tearDown=tearDown, tags=tags)
+            bm = Benchmark(
+                fn,
+                name=name,
+                params=params,
+                setUp=setUp,
+                tearDown=tearDown,
+                tags=tags,
+                state=state,
+            )
             benchmarks.append(bm)
         return benchmarks
 
@@ -224,7 +239,8 @@ def decorator(fn: Callable) -> list[Benchmark]:
         benchmarks = []
         names = set()
         varnames = iterables.keys()
-        for values in itertools.product(*iterables.values()):
+        cartesian_product = list(itertools.product(*iterables.values()))
+        for idx, values in enumerate(cartesian_product):
             params = dict(zip(varnames, values))
             _check_against_interface(params, fn)
 
@@ -235,8 +251,23 @@ def decorator(fn: Callable) -> list[Benchmark]:
                     f"Perhaps you specified a parameter configuration twice?"
                 )
             names.add(name)
+            state = State(
+                name=name,
+                function=fn,
+                family=fn.__name__,
+                family_size=len(cartesian_product),
+                family_index=idx,
+            )
 
-            bm = Benchmark(fn, name=name, params=params, setUp=setUp, tearDown=tearDown, tags=tags)
+            bm = Benchmark(
+                fn,
+                name=name,
+                params=params,
+                setUp=setUp,
+                tearDown=tearDown,
+                tags=tags,
+                state=state,
+            )
             benchmarks.append(bm)
         return benchmarks
 

src/nnbench/types/__init__.py

@@ -1 +1 @@
-from .types import Benchmark, BenchmarkRecord, Memo, Parameters
+from .types import Benchmark, BenchmarkRecord, Memo, Parameters, State

src/nnbench/types/types.py

@@ -14,6 +14,7 @@
     TypeVar,
 )
 
+from nnbench import __version__
 from nnbench.context import Context
 
 T = TypeVar("T")
@@ -101,6 +102,16 @@ def expand(cls, bms: list[dict[str, Any]]) -> BenchmarkRecord:
     #  context data.
 
 
+@dataclass(frozen=True)
+class State:
+    name: str
+    function: Callable[..., Any]
+    family: str
+    family_size: int
+    family_index: int
+    nnbench_version: str = __version__
+
+
 class Memo(Generic[T]):
     @functools.cache
     # TODO: Swap this out for a local type-wide memo cache.
@@ -164,11 +175,41 @@ class Benchmark:
     tearDown: Callable[..., None] = field(repr=False, default=NoOp)
     tags: tuple[str, ...] = field(repr=False, default=())
     interface: Interface = field(init=False, repr=False)
+    state: State | None = field(default=None)
 
     def __post_init__(self):
         if not self.name:
             super().__setattr__("name", self.fn.__name__)
         super().__setattr__("interface", Interface.from_callable(self.fn, self.params))
+        if not self.state:
+            super().__setattr__(
+                "state",
+                State(
+                    name=self.name or "",
+                    function=self.fn,
+                    family=self.fn.__name__,
+                    family_size=1,
+                    family_index=0,
+                ),
+            )
+
+        original_setUp = self.setUp
+
+        def wrapped_setUp(*args: Any, **kwargs: Any) -> None:
+            state = self.state
+            # TODO: setUp logic
+            original_setUp(*args, **kwargs)
+
+        super().__setattr__("setUp", wrapped_setUp)
+
+        original_tearDown = self.tearDown
+
+        def wrapped_tearDown(*args: Any, **kwargs: Any) -> None:
+            state = self.state
+            # TODO: tearDown logic
+            original_tearDown(*args, **kwargs)
+
+        super().__setattr__("tearDown", wrapped_tearDown)
 
 
 @dataclass(frozen=True)