common: Add unique function

src/tests/common/unique_function.cpp

@@ -0,0 +1,108 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <string>
+
+#include <catch2/catch.hpp>
+
+#include "common/unique_function.h"
+
+namespace {
+struct Noisy {
+    Noisy() : state{"Default constructed"} {}
+    Noisy(Noisy&& rhs) noexcept : state{"Move constructed"} {
+        rhs.state = "Moved away";
+    }
+    Noisy& operator=(Noisy&& rhs) noexcept {
+        state = "Move assigned";
+        rhs.state = "Moved away";
+    }
+    Noisy(const Noisy&) : state{"Copied constructed"} {}
+    Noisy& operator=(const Noisy&) {
+        state = "Copied assigned";
+    }
+
+    std::string state;
+};
+} // Anonymous namespace
+
+TEST_CASE("UniqueFunction", "[common]") {
+    SECTION("Capture reference") {
+        int value = 0;
+        Common::UniqueFunction<void> func = [&value] { value = 5; };
+        func();
+        REQUIRE(value == 5);
+    }
+    SECTION("Capture pointer") {
+        int value = 0;
+        int* pointer = &value;
+        Common::UniqueFunction<void> func = [pointer] { *pointer = 5; };
+        func();
+        REQUIRE(value == 5);
+    }
+    SECTION("Move object") {
+        Noisy noisy;
+        REQUIRE(noisy.state == "Default constructed");
+
+        Common::UniqueFunction<void> func = [noisy = std::move(noisy)] {
+            REQUIRE(noisy.state == "Move constructed");
+        };
+        REQUIRE(noisy.state == "Moved away");
+        func();
+    }
+    SECTION("Move construct function") {
+        int value = 0;
+        Common::UniqueFunction<void> func = [&value] { value = 5; };
+        Common::UniqueFunction<void> new_func = std::move(func);
+        new_func();
+        REQUIRE(value == 5);
+    }
+    SECTION("Move assign function") {
+        int value = 0;
+        Common::UniqueFunction<void> func = [&value] { value = 5; };
+        Common::UniqueFunction<void> new_func;
+        new_func = std::move(func);
+        new_func();
+        REQUIRE(value == 5);
+    }
+    SECTION("Default construct then assign function") {
+        int value = 0;
+        Common::UniqueFunction<void> func;
+        func = [&value] { value = 5; };
+        func();
+        REQUIRE(value == 5);
+    }
+    SECTION("Pass arguments") {
+        int result = 0;
+        Common::UniqueFunction<void, int, int> func = [&result](int a, int b) { result = a + b; };
+        func(5, 4);
+        REQUIRE(result == 9);
+    }
+    SECTION("Pass arguments and return value") {
+        Common::UniqueFunction<int, int, int> func = [](int a, int b) { return a + b; };
+        REQUIRE(func(5, 4) == 9);
+    }
+    SECTION("Destructor") {
+        int num_destroyed = 0;
+        struct Foo {
+            Foo(int* num_) : num{num_} {}
+            Foo(Foo&& rhs) : num{std::exchange(rhs.num, nullptr)} {}
+            Foo(const Foo&) = delete;
+
+            ~Foo() {
+                if (num) {
+                    ++*num;
+                }
+            }
+
+            int* num = nullptr;
+        };
+        Foo object{&num_destroyed};
+        {
+            Common::UniqueFunction<void> func = [object = std::move(object)] {};
+            REQUIRE(num_destroyed == 0);
+        }
+        REQUIRE(num_destroyed == 1);
+    }
+}