covering test for deffered strategy draw

Author: tybug

hypothesis-python/tests/cover/test_searchstrategy.py

@@ -17,19 +17,18 @@
 import attr
 import pytest
 
-from hypothesis import given
+from hypothesis import given, strategies as st
 from hypothesis.errors import InvalidArgument, Unsatisfiable
 from hypothesis.internal.conjecture.data import ConjectureData
 from hypothesis.internal.reflection import get_pretty_function_description
-from hypothesis.strategies import booleans, data, integers, just, lists, none, tuples
 from hypothesis.strategies._internal.utils import to_jsonable
 
 from tests.common.debug import assert_simple_property, check_can_generate_examples
 from tests.common.utils import checks_deprecated_behaviour
 
 
 def test_or_errors_when_given_non_strategy():
-    bools = tuples(booleans())
+    bools = st.tuples(st.booleans())
     with pytest.raises(ValueError):
         bools | "foo"
 
@@ -49,29 +48,29 @@ class WeirdRepr:
         def __repr__(self):
             return "ABCDEFG"
 
-    assert repr(just(WeirdRepr())) == f"just({WeirdRepr()!r})"
+    assert repr(st.just(WeirdRepr())) == f"just({WeirdRepr()!r})"
 
 
 def test_just_strategy_does_not_draw():
     data = ConjectureData.for_choices([])
-    s = just("hello")
+    s = st.just("hello")
     assert s.do_draw(data) == "hello"
 
 
 def test_none_strategy_does_not_draw():
     data = ConjectureData.for_choices([])
-    s = none()
+    s = st.none()
     assert s.do_draw(data) is None
 
 
 def test_can_map():
-    s = integers().map(pack=lambda t: "foo")
+    s = st.integers().map(pack=lambda t: "foo")
     assert_simple_property(s, lambda v: v == "foo")
 
 
 def test_example_raises_unsatisfiable_when_too_filtered():
     with pytest.raises(Unsatisfiable):
-        check_can_generate_examples(integers().filter(lambda x: False))
+        check_can_generate_examples(st.integers().filter(lambda x: False))
 
 
 def nameless_const(x):
@@ -83,20 +82,20 @@ def f(u, v):
 
 def test_can_map_nameless():
     f = nameless_const(2)
-    assert get_pretty_function_description(f) in repr(integers().map(f))
+    assert get_pretty_function_description(f) in repr(st.integers().map(f))
 
 
 def test_can_flatmap_nameless():
-    f = nameless_const(just(3))
-    assert get_pretty_function_description(f) in repr(integers().flatmap(f))
+    f = nameless_const(st.just(3))
+    assert get_pretty_function_description(f) in repr(st.integers().flatmap(f))
 
 
 def test_flatmap_with_invalid_expand():
     with pytest.raises(InvalidArgument):
-        check_can_generate_examples(just(100).flatmap(lambda n: "a"))
+        check_can_generate_examples(st.just(100).flatmap(lambda n: "a"))
 
 
-_bad_random_strategy = lists(integers(), min_size=1).map(random.choice)
+_bad_random_strategy = st.lists(st.integers(), min_size=1).map(random.choice)
 
 
 @checks_deprecated_behaviour
@@ -106,7 +105,7 @@ def test_use_of_global_random_is_deprecated_in_given():
 
 @checks_deprecated_behaviour
 def test_use_of_global_random_is_deprecated_in_interactive_draws():
-    @given(data())
+    @given(st.data())
     def inner(d):
         d.draw(_bad_random_strategy)
 
@@ -178,3 +177,8 @@ def test_jsonable_override():
     obj = HasCustomJsonFormat("expected")
     assert to_jsonable(obj, avoid_realization=False) == "surprise!"
     assert to_jsonable(obj, avoid_realization=True) == "<symbolic>"
+
+
+def test_deferred_strategy_draw():
+    strategy = st.deferred(lambda: st.integers())
+    assert strategy.do_draw(ConjectureData.for_choices([0])) == 0