[libcxx-commits] [libcxx] [libc++][test] Refactor tests for ranges::swap_range algorithms (PR #121138)

[Louis Dionne via libcxx-commits]

================
@@ -51,72 +47,110 @@ auto can_swap_test(...) -> std::false_type;
 
 template <class Tp>
 constexpr bool can_swap() {
-    return std::is_same<decltype(can_swap_test<Tp>(0)), void>::value;
+  return std::is_same<decltype(can_swap_test<Tp>(0)), void>::value;
+}
+
+TEST_CONSTEXPR_CXX23 void test_unique_ptr() {
+  std::unique_ptr<int> i[3];
+  for (int k = 0; k < 3; ++k)
+    i[k].reset(new int(k + 1));
+  std::unique_ptr<int> j[3];
+  for (int k = 0; k < 3; ++k)
+    j[k].reset(new int(k + 4));
+  std::swap(i, j);
+  assert(*i[0] == 4);
+  assert(*i[1] == 5);
+  assert(*i[2] == 6);
+  assert(*j[0] == 1);
+  assert(*j[1] == 2);
+  assert(*j[2] == 3);
 }
 #endif
 
-#if TEST_STD_VER > 17
-constexpr bool test_swap_constexpr()
-{
+TEST_CONSTEXPR_CXX20 bool test() {
+  {
     int i[3] = {1, 2, 3};
     int j[3] = {4, 5, 6};
     std::swap(i, j);
-    return i[0] == 4 &&
-           i[1] == 5 &&
-           i[2] == 6 &&
-           j[0] == 1 &&
-           j[1] == 2 &&
-           j[2] == 3;
-}
-#endif // TEST_STD_VER > 17
-
-int main(int, char**)
-{
-    {
-        int i[3] = {1, 2, 3};
-        int j[3] = {4, 5, 6};
-        std::swap(i, j);
-        assert(i[0] == 4);
-        assert(i[1] == 5);
-        assert(i[2] == 6);
-        assert(j[0] == 1);
-        assert(j[1] == 2);
-        assert(j[2] == 3);
-    }
+    assert(i[0] == 4);
+    assert(i[1] == 5);
+    assert(i[2] == 6);
+    assert(j[0] == 1);
+    assert(j[1] == 2);
+    assert(j[2] == 3);
+  }
+  {
+    int a[2][2]   = {{0, 1}, {2, 3}};
+    decltype(a) b = {{9, 8}, {7, 6}};
+
+    std::swap(a, b);
+
+    assert(a[0][0] == 9);
+    assert(a[0][1] == 8);
+    assert(a[1][0] == 7);
+    assert(a[1][1] == 6);
+
+    assert(b[0][0] == 0);
+    assert(b[0][1] == 1);
+    assert(b[1][0] == 2);
+    assert(b[1][1] == 3);
+  }
+
+  {
+    int a[3][3]   = {{0, 1, 2}, {3, 4, 5}, {6, 7, 8}};
+    decltype(a) b = {{9, 8, 7}, {6, 5, 4}, {3, 2, 1}};
+
+    std::swap(a, b);
+
+    assert(a[0][0] == 9);
+    assert(a[0][1] == 8);
+    assert(a[0][2] == 7);
+    assert(a[1][0] == 6);
+    assert(a[1][1] == 5);
+    assert(a[1][2] == 4);
+    assert(a[2][0] == 3);
+    assert(a[2][1] == 2);
+    assert(a[2][2] == 1);
+
+    assert(b[0][0] == 0);
+    assert(b[0][1] == 1);
+    assert(b[0][2] == 2);
+    assert(b[1][0] == 3);
+    assert(b[1][1] == 4);
+    assert(b[1][2] == 5);
+    assert(b[2][0] == 6);
+    assert(b[2][1] == 7);
+    assert(b[2][2] == 8);
+  }
 #if TEST_STD_VER >= 11
-    {
-        std::unique_ptr<int> i[3];
-        for (int k = 0; k < 3; ++k)
-            i[k].reset(new int(k+1));
-        std::unique_ptr<int> j[3];
-        for (int k = 0; k < 3; ++k)
-            j[k].reset(new int(k+4));
-        std::swap(i, j);
-        assert(*i[0] == 4);
-        assert(*i[1] == 5);
-        assert(*i[2] == 6);
-        assert(*j[0] == 1);
-        assert(*j[1] == 2);
-        assert(*j[2] == 3);
-    }
-    {
-        using CA = CopyOnly[42];
-        using MA = NoexceptMoveOnly[42];
-        using NA = NotMoveConstructible[42];
-        static_assert(can_swap<CA&>(), "");
-        static_assert(can_swap<MA&>(), "");
-        static_assert(!can_swap<NA&>(), "");
-
-        CA ca;
-        MA ma;
-        static_assert(!noexcept(std::swap(ca, ca)), "");
-        static_assert(noexcept(std::swap(ma, ma)), "");
-    }
+  {
+    using CA = CopyOnly[42];
+    using MA = NoexceptMoveOnly[42];
+    using NA = NotMoveConstructible[42];
+    static_assert(can_swap<CA&>(), "");
+    static_assert(can_swap<MA&>(), "");
+    static_assert(!can_swap<NA&>(), "");
+
+    CA ca;
+    MA ma;
+    static_assert(!noexcept(std::swap(ca, ca)), "");
+    static_assert(noexcept(std::swap(ma, ma)), "");
+  }
+
+  // `unique_ptr` is constexpr only since C++23, so we can't inline `test_unique_ptr()` into `test()`
+  // because `test()` is constexpr since C++20.
----------------
ldionne wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/121138