add unit tests for optional type

Makefile

@@ -59,12 +59,14 @@ bench: out/bench-variant out/unique_ptr_test out/unique_ptr_test out/recursive_w
 	./out/recursive_wrapper_test 100000
 	./out/binary_visitor_test 100000
 
-out/unit: Makefile test/unit.cpp variant.hpp
+out/unit: Makefile test/unit.cpp test/optional_unit.cpp optional.hpp variant.hpp
 	mkdir -p ./out
 	$(CXX) -o out/unit test/unit.cpp -I./ $(RELEASE_FLAGS) $(COMMON_FLAGS) $(CXXFLAGS) $(LDFLAGS)
+	$(CXX) -o out/optional_unit test/optional_unit.cpp -I./ $(RELEASE_FLAGS) $(COMMON_FLAGS) $(CXXFLAGS) $(LDFLAGS)
 
 test: out/unit
 	./out/unit
+	./out/optional_unit
 
 sizes: Makefile variant.hpp
 	mkdir -p ./out

test/optional_unit.cpp

@@ -0,0 +1,71 @@
+#define CATCH_CONFIG_RUNNER
+#include "catch.hpp"
+
+#include "optional.hpp"
+
+using namespace mapbox;
+
+struct dummy {
+    dummy(int _m_1, int _m_2) : m_1(_m_1), m_2(_m_2) {}
+    int m_1;
+    int m_2;
+
+};
+
+int main (int argc, char* const argv[])
+{
+    int result = Catch::Session().run(argc, argv);
+    if (!result) printf("\x1b[1;32m ✓ \x1b[0m\n");
+    return result;
+}
+
+TEST_CASE( "optional can be instantiated with a POD type", "[optiona]" ) {
+    mapbox::util::optional<double> dbl_opt;
+
+    REQUIRE(!dbl_opt);
+    dbl_opt = 3.1415;
+    REQUIRE(dbl_opt);
+
+    REQUIRE(dbl_opt.get() == 3.1415);
+    REQUIRE(*dbl_opt == 3.1415);
+}
+
+TEST_CASE( "copy c'tor", "[optiona]" ) {
+    mapbox::util::optional<double> dbl_opt;
+
+    REQUIRE(!dbl_opt);
+    dbl_opt = 3.1415;
+    REQUIRE(dbl_opt);
+
+    mapbox::util::optional<double> other = dbl_opt;
+
+    REQUIRE(other.get() == 3.1415);
+    REQUIRE(*other == 3.1415);
+}
+
+TEST_CASE( "const operator*, const get()", "[optiona]" ) {
+    mapbox::util::optional<double> dbl_opt = 3.1415;
+
+    REQUIRE(dbl_opt);
+
+    const double pi1 = dbl_opt.get();
+    const double pi2 = *dbl_opt;
+
+    REQUIRE(pi1 == 3.1415);
+    REQUIRE(pi2 == 3.1415);
+}
+
+TEST_CASE( "emplace initialization, reset", "[optional]" ) {
+    mapbox::util::optional<dummy> dummy_opt;
+    REQUIRE(!dummy_opt);
+
+    // rvalues, baby!
+    dummy_opt.emplace(1, 2);
+    REQUIRE(dummy_opt);
+    REQUIRE(dummy_opt.get().m_1 == 1);
+    REQUIRE((*dummy_opt).m_2 == 2);
+
+    dummy_opt.reset();
+    REQUIRE(!dummy_opt);
+
+}