Squashed 'third_party/optional/' content from commit 1baad184f

Change-Id: I9b2473a84dcf6d9892f1f7a9fd21b340796b6ff5
git-subtree-dir: third_party/optional
git-subtree-split: 1baad184f022a3a7502db094a984a86adedf9626
diff --git a/tests/in_place.cpp b/tests/in_place.cpp
new file mode 100644
index 0000000..07254e4
--- /dev/null
+++ b/tests/in_place.cpp
@@ -0,0 +1,41 @@
+#include "catch.hpp"
+#include "optional.hpp"
+
+#include <tuple>
+#include <vector>
+
+struct takes_init_and_variadic {
+  std::vector<int> v;
+  std::tuple<int, int> t;
+  template <class... Args>
+  takes_init_and_variadic(std::initializer_list<int> l, Args &&... args)
+      : v(l), t(std::forward<Args>(args)...) {}
+};
+
+TEST_CASE("In place", "[in_place]") {
+  tl::optional<int> o1{tl::in_place};
+  tl::optional<int> o2(tl::in_place);
+  REQUIRE(o1);
+  REQUIRE(o1 == 0);
+  REQUIRE(o2);
+  REQUIRE(o2 == 0);
+
+  tl::optional<int> o3(tl::in_place, 42);
+  REQUIRE(o3 == 42);
+
+  tl::optional<std::tuple<int, int>> o4(tl::in_place, 0, 1);
+  REQUIRE(o4);
+  REQUIRE(std::get<0>(*o4) == 0);
+  REQUIRE(std::get<1>(*o4) == 1);
+
+  tl::optional<std::vector<int>> o5(tl::in_place, {0, 1});
+  REQUIRE(o5);
+  REQUIRE((*o5)[0] == 0);
+  REQUIRE((*o5)[1] == 1);
+
+  tl::optional<takes_init_and_variadic> o6(tl::in_place, {0, 1}, 2, 3);
+  REQUIRE(o6->v[0] == 0);
+  REQUIRE(o6->v[1] == 1);
+  REQUIRE(std::get<0>(o6->t) == 2);
+  REQUIRE(std::get<1>(o6->t) == 3);
+}