intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 69 insertions, 0 deletions

diff --git a/util/generic/function_ut.cpp b/util/generic/function_ut.cpp
new file mode 100644
index 00000000000..3880295a9fc
--- /dev/null
+++ b/util/generic/function_ut.cpp
@@ -0,0 +1,69 @@
+#include "function.h"
+#include "typetraits.h"
+
+#include <library/cpp/testing/unittest/registar.h>
+
+Y_UNIT_TEST_SUITE(TestFunctionSignature) {
+    int FF(double x) {
+        return (int)x;
+    }
+
+    int FFF(double x, char xx) {
+        return (int)x + (int)xx;
+    }
+
+    struct A {
+        int F(double x) {
+            return FF(x);
+        }
+    };
+
+    Y_UNIT_TEST(TestPlainFunc) {
+        UNIT_ASSERT_TYPES_EQUAL(TFunctionSignature<decltype(FF)>, decltype(FF));
+    }
+
+    Y_UNIT_TEST(TestMethod) {
+        UNIT_ASSERT_TYPES_EQUAL(TFunctionSignature<decltype(&A::F)>, decltype(FF));
+    }
+
+    Y_UNIT_TEST(TestLambda) {
+        auto f = [](double x) -> int {
+            return FF(x);
+        };
+
+        UNIT_ASSERT_TYPES_EQUAL(TFunctionSignature<decltype(f)>, decltype(FF));
+    }
+
+    Y_UNIT_TEST(TestFunction) {
+        std::function<int(double)> f(FF);
+
+        UNIT_ASSERT_TYPES_EQUAL(TFunctionSignature<decltype(f)>, decltype(FF));
+    }
+
+    template <class F>
+    void TestCT() {
+#define FA(x) TFunctionArg<F, x>
+
+        UNIT_ASSERT_TYPES_EQUAL(FA(0), double);
+        UNIT_ASSERT_TYPES_EQUAL(FA(1), char);
+        UNIT_ASSERT_TYPES_EQUAL(TFunctionResult<F>, int);
+
+#undef FA
+    }
+
+    Y_UNIT_TEST(TestTypeErasureTraits) {
+        TestCT<std::function<int(double, char)>>();
+    }
+
+    Y_UNIT_TEST(TestPlainFunctionTraits) {
+        TestCT<decltype(FFF)>();
+    }
+
+    Y_UNIT_TEST(TestLambdaTraits) {
+        auto fff = [](double xx, char xxx) -> int {
+            return FFF(xx, xxx);
+        };
+
+        TestCT<decltype(fff)>();
+    }
+}