Squashed 'third_party/GSL/' content from commit 0cebbd7

Change-Id: Iffb2e32f2f45297ac6d3e82168cd9df4ac5acc2f
git-subtree-dir: third_party/GSL
git-subtree-split: 0cebbd77bfc21acbf1cc05983ad626539eeeb8e0
diff --git a/tests/utils_tests.cpp b/tests/utils_tests.cpp
new file mode 100644
index 0000000..587b0a1
--- /dev/null
+++ b/tests/utils_tests.cpp
@@ -0,0 +1,120 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
+
+#include <gsl/gsl_util> // for narrow, finally, narrow_cast, narrowing_e...
+
+#include <algorithm>   // for move
+#include <functional>  // for reference_wrapper, _Bind_helper<>::type
+#include <limits>      // for numeric_limits
+#include <stdint.h>    // for uint32_t, int32_t
+#include <type_traits> // for is_same
+
+using namespace gsl;
+
+TEST_CASE("sanity check for gsl::index typedef")
+{
+    static_assert(std::is_same<gsl::index, std::ptrdiff_t>::value,
+                  "gsl::index represents wrong arithmetic type");
+}
+
+void f(int& i) { i += 1; }
+
+TEST_CASE("finally_lambda")
+{
+    int i = 0;
+    {
+        auto _ = finally([&]() { f(i); });
+        CHECK(i == 0);
+    }
+    CHECK(i == 1);
+}
+
+TEST_CASE("finally_lambda_move")
+{
+    int i = 0;
+    {
+        auto _1 = finally([&]() { f(i); });
+        {
+            auto _2 = std::move(_1);
+            CHECK(i == 0);
+        }
+        CHECK(i == 1);
+        {
+            auto _2 = std::move(_1);
+            CHECK(i == 1);
+        }
+        CHECK(i == 1);
+    }
+    CHECK(i == 1);
+}
+
+TEST_CASE("finally_function_with_bind")
+{
+    int i = 0;
+    {
+        auto _ = finally(std::bind(&f, std::ref(i)));
+        CHECK(i == 0);
+    }
+    CHECK(i == 1);
+}
+
+int j = 0;
+void g() { j += 1; }
+TEST_CASE("finally_function_ptr")
+{
+    j = 0;
+    {
+        auto _ = finally(&g);
+        CHECK(j == 0);
+    }
+    CHECK(j == 1);
+}
+
+TEST_CASE("narrow_cast")
+{
+    int n = 120;
+    char c = narrow_cast<char>(n);
+    CHECK(c == 120);
+
+    n = 300;
+    unsigned char uc = narrow_cast<unsigned char>(n);
+    CHECK(uc == 44);
+}
+
+TEST_CASE("narrow")
+{
+    int n = 120;
+    const char c = narrow<char>(n);
+    CHECK(c == 120);
+
+    n = 300;
+    CHECK_THROWS_AS(narrow<char>(n), narrowing_error);
+
+    const auto int32_max = std::numeric_limits<int32_t>::max();
+    const auto int32_min = std::numeric_limits<int32_t>::min();
+
+    CHECK(narrow<uint32_t>(int32_t(0)) == 0);
+    CHECK(narrow<uint32_t>(int32_t(1)) == 1);
+    CHECK(narrow<uint32_t>(int32_max) == static_cast<uint32_t>(int32_max));
+
+    CHECK_THROWS_AS(narrow<uint32_t>(int32_t(-1)), narrowing_error);
+    CHECK_THROWS_AS(narrow<uint32_t>(int32_min), narrowing_error);
+
+    n = -42;
+    CHECK_THROWS_AS(narrow<unsigned>(n), narrowing_error);
+}