Various core and test changes

hypothesis-python/RELEASE.rst

@@ -0,0 +1,3 @@
+RELEASE_TYPE: patch
+
+This patch refactors some internals, continuing our work on supporting alternative backends (:issue:`3086`). There is no user-visible change.

hypothesis-python/src/hypothesis/internal/conjecture/data.py

@@ -30,6 +30,7 @@
     Set,
     Tuple,
     Type,
+    TypeVar,
     Union,
 )
 
@@ -88,6 +89,8 @@ def wrapper(tp):
 ]
 TargetObservations = Dict[Optional[str], Union[int, float]]
 
+T = TypeVar("T")
+
 
 class ExtraInformation:
     """A class for holding shared state on a ``ConjectureData`` that should
@@ -1719,6 +1722,11 @@ def freeze(self) -> None:
         self.buffer = bytes(self.buffer)
         self.observer.conclude_test(self.status, self.interesting_origin)
 
+    def choice(self, values: Sequence[T], *, forced: Optional[T] = None) -> T:
+        forced_i = None if forced is None else values.index(forced)
+        i = self.draw_integer(0, len(values) - 1, forced=forced_i)
+        return values[i]
+
     def draw_bits(self, n: int, *, forced: Optional[int] = None) -> int:
         """Return an ``n``-bit integer from the underlying source of
         bytes. If ``forced`` is set to an integer will instead

hypothesis-python/src/hypothesis/internal/conjecture/utils.py

@@ -81,14 +81,6 @@ def check_sample(
     return tuple(values)
 
 
-def choice(
-    data: "ConjectureData", values: Sequence[T], *, forced: Optional[T] = None
-) -> T:
-    forced_i = None if forced is None else values.index(forced)
-    i = data.draw_integer(0, len(values) - 1, forced=forced_i)
-    return values[i]
-
-
 class Sampler:
     """Sampler based on Vose's algorithm for the alias method. See
     http://www.keithschwarz.com/darts-dice-coins/ for a good explanation.
@@ -182,8 +174,8 @@ def sample(self, data: "ConjectureData", forced: Optional[int] = None) -> int:
             if forced is None
             else next((b, a, a_c) for (b, a, a_c) in self.table if forced in (b, a))
         )
-        base, alternate, alternate_chance = choice(
-            data, self.table, forced=forced_choice
+        base, alternate, alternate_chance = data.choice(
+            self.table, forced=forced_choice
         )
         use_alternate = data.draw_boolean(
             alternate_chance, forced=None if forced is None else forced == alternate

hypothesis-python/src/hypothesis/strategies/_internal/strategies.py

@@ -586,7 +586,7 @@ def do_filtered_draw(self, data):
         # The speculative index didn't work out, but at this point we've built
         # and can choose from the complete list of allowed indices and elements.
         if allowed:
-            i, element = cu.choice(data, allowed)
+            i, element = data.choice(allowed)
             data.draw_integer(0, len(self.elements) - 1, forced=i)
             return element
         # If there are no allowed indices, the filter couldn't be satisfied.

hypothesis-python/tests/common/debug.py

@@ -22,15 +22,20 @@ class Timeout(BaseException):
 
 
 def minimal(definition, condition=lambda x: True, settings=None, timeout_after=10):
+    definition.validate()
+    runtime = None
+    result = None
+
     def wrapped_condition(x):
+        nonlocal runtime
         if timeout_after is not None:
             if runtime:
-                runtime[0] += TIME_INCREMENT
-                if runtime[0] >= timeout_after:
+                runtime += TIME_INCREMENT
+                if runtime >= timeout_after:
                     raise Timeout
         result = condition(x)
         if result and not runtime:
-            runtime.append(0.0)
+            runtime = 0.0
         return result
 
     if settings is None:
@@ -51,16 +56,14 @@ def wrapped_condition(x):
     )
     def inner(x):
         if wrapped_condition(x):
-            result[:] = [x]
+            nonlocal result
+            result = x
             raise Found
 
-    definition.validate()
-    runtime = []
-    result = []
     try:
         inner()
     except Found:
-        return result[0]
+        return result
     raise Unsatisfiable(
         "Could not find any examples from %r that satisfied %s"
         % (definition, get_pretty_function_description(condition))