merge(3p/immer): Subtree merge at 'ad3e3556d' as 'third_party/immer'

Change-Id: I9636a41ad44b4218293833fd3e9456d9b07c731b

third_party/immer/test/atom/generic.ipp

@@ -0,0 +1,53 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#ifndef ATOM_T
+#error "define the box template to use in ATOM_T"
+#endif
+
+#include <catch.hpp>
+
+template <typename T>
+using BOX_T = typename ATOM_T<T>::box_type;
+
+TEST_CASE("construction") { ATOM_T<int> x; }
+
+TEST_CASE("store, load, exchange")
+{
+    ATOM_T<int> x;
+    CHECK(x.load() == BOX_T<int>{0});
+    x.store(42);
+    CHECK(x.load() == BOX_T<int>{42});
+    auto old = x.exchange(12);
+    CHECK(old == 42);
+    CHECK(x.load() == BOX_T<int>{12});
+}
+
+TEST_CASE("box conversion")
+{
+    ATOM_T<int> x;
+    auto v1 = BOX_T<int>{42};
+    x       = v1;
+    auto v2 = BOX_T<int>{x};
+    CHECK(v1 == v2);
+}
+
+TEST_CASE("value conversion")
+{
+    ATOM_T<int> x;
+    x      = 42;
+    auto v = int{x};
+    CHECK(v == 42);
+}
+
+TEST_CASE("update")
+{
+    ATOM_T<int> x{42};
+    x.update([](auto x) { return x + 2; });
+    CHECK(x.load() == 44);
+}