From b5d1fe4e5cc7749a80f6b31c0871201b02a9a864 Mon Sep 17 00:00:00 2001
From: Luke Valenty <luke.valenty@intel.com>
Date: Tue, 1 Oct 2024 11:27:03 -0700
Subject: [PATCH] Add a few property based tests stressing template parameter
 packs.

Requires the `hypothesis` python module.
---
 test/test_rand_templates.py | 106 ++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 test/test_rand_templates.py

diff --git a/test/test_rand_templates.py b/test/test_rand_templates.py
new file mode 100644
index 00000000..6d1a3a97
--- /dev/null
+++ b/test/test_rand_templates.py
@@ -0,0 +1,106 @@
+import hypothesis
+from hypothesis import given, settings, example, note, strategies as st
+import cppyy
+import pytest
+
+cppyy.cppdef("""
+    namespace test {
+    template <typename T>
+    constexpr std::size_t tuple_size(const T&) {
+        return std::tuple_size<T>::value;
+    }
+
+    constexpr bool as_bool(auto b) {
+        return static_cast<bool>(b);
+    }
+
+    template<typename... Ts>
+    struct list {
+        template<typename... Us>
+        constexpr auto operator==(list<Us...>) const -> bool {
+            return false;
+        }
+
+        constexpr auto operator==(list<Ts...>) const -> bool {
+            return true;
+        }
+    };
+
+    template<typename... Ts>
+    constexpr auto make_list(Ts...) {
+        return list<Ts...>{};
+    }
+
+    template<typename... Ls, typename... Rs>
+    constexpr auto cat(list<Ls...>, list<Rs...>) {
+        return list<Ls..., Rs...>{};
+    }
+    } // namespace test
+""")
+
+class TestRandomTemplates:
+    bools = st.booleans().map(lambda v: cppyy.gbl.test.as_bool(v))
+
+    def make_c_type_strat(t):
+        min_val = cppyy.gbl.std.numeric_limits[t].min()
+        max_val = cppyy.gbl.std.numeric_limits[t].max()
+        return st.integers(min_value=int(min_val), max_value=int(max_val)).map(lambda v: t(v))
+
+    int16s = make_c_type_strat(cppyy.gbl.std.int16_t)
+    int32s = make_c_type_strat(cppyy.gbl.std.int32_t)
+    int64s = make_c_type_strat(cppyy.gbl.std.int64_t)
+
+    uint16s = make_c_type_strat(cppyy.gbl.std.uint16_t)
+    uint32s = make_c_type_strat(cppyy.gbl.std.uint32_t)
+    uint64s = make_c_type_strat(cppyy.gbl.std.uint64_t)
+
+    cpp_primitives = st.one_of(bools, int16s, int32s, int64s, uint16s, uint32s, uint64s)
+
+    @classmethod
+    def as_std_tuple_tree(cls, value):
+        if isinstance(value, list):
+            values = [cls.as_std_tuple_tree(v) for v in value]
+            return std.make_tuple(*values)
+        else:
+            return value
+
+    @classmethod
+    def as_test_list_tree(cls, value):
+        if isinstance(value, list):
+            values = [cls.as_test_list_tree(v) for v in value]
+            return cppyy.gbl.test.make_list[tuple(type(v) for v in values)](*values)
+        else:
+            return value
+
+    @st.composite
+    def py_list_trees(draw, leaves=cpp_primitives):
+        t = draw(st.recursive(leaves, lambda children: st.lists(children)))
+        
+        if not isinstance(t, list):
+            t = [t]
+
+        return t
+
+    # TODO: uncomment once #261 is fixed
+    # @given(st.lists(cpp_primitives))
+    # def test_std_tuple_size(pytestconfig, ints):
+    #     assert cppyy.gbl.test.tuple_size(cppyy.gbl.std.make_tuple(*ints)) == len(ints)
+
+    # TODO: uncomment once #261 is fixed
+    # @classmethod
+    # @settings(deadline=2000)
+    # @given(py_list_trees(), py_list_trees())
+    # @example([0], [[], []])
+    # def test_std_tuple_cat(cls, pytestconfig, left, right):
+    #     expected = cls.as_std_tuple_tree(left + right)
+    #     actual = cppyy.gbl.std.tuple_cat(cls.as_std_tuple_tree(left), cls.as_std_tuple_tree(right))
+    #     assert actual == expected
+
+    @classmethod
+    @settings(deadline=2000)
+    @given(py_list_trees(), py_list_trees())
+    @example([0], [[], []])
+    def test_list_cat(cls, pytestconfig, left, right):
+        expected = cls.as_test_list_tree(left + right)
+        actual = cppyy.gbl.test.cat(cls.as_test_list_tree(left), cls.as_test_list_tree(right))
+        assert actual == expected