Add tests

test/libsolutil/LazyInit.cpp

@@ -15,13 +15,103 @@
 	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <libsolutil/LazyInit.h>
+
 #include <boost/test/unit_test.hpp>
 
+#include <utility>
+
 namespace solidity::util::test
 {
 
-BOOST_AUTO_TEST_SUITE(LazyInit)
+namespace
+{
 
+template<typename T>
+void assertInitCalled(LazyInit<T> lazyInit, bool target)
+{
+	bool initCalled = false;
+
+	lazyInit.init([&]{
+	  initCalled = true;
+	  return T();
+	});
+
+	BOOST_REQUIRE_EQUAL(initCalled, target);
+}
+
+// Take ownership to ensure that it doesn't "mutate"
+template<typename T>
+void assertNotEmpty(LazyInit<T> _lazyInit) { assertInitCalled(std::move(_lazyInit), false); }
+
+// Take ownership to ensure that it doesn't "mutate"
+template<typename T>
+void assertEmpty(LazyInit<T> _lazyInit) { assertInitCalled(std::move(_lazyInit), true); }
+
+template<typename T>
+T valueOf(LazyInit<T> _lazyInit)
+{
+	return _lazyInit.init([&]{
+		BOOST_REQUIRE(false); // this should never be called
+		return T();
+	});
+}
+
+}
+
+BOOST_AUTO_TEST_SUITE(LazyInitTests)
+
+BOOST_AUTO_TEST_CASE(default_constructed_is_empty)
+{
+	assertEmpty(LazyInit<int>());
+	assertEmpty(LazyInit<int const>());
+}
+
+BOOST_AUTO_TEST_CASE(initialized_is_not_empty)
+{
+	LazyInit<int> lazyInit;
+	lazyInit.init([]{ return 12; });
+
+	assertNotEmpty(std::move(lazyInit));
+}
+
+BOOST_AUTO_TEST_CASE(init_returns_init_value)
+{
+	LazyInit<int> lazyInit;
+
+	BOOST_CHECK_EQUAL(lazyInit.init([]{ return 12; }), 12);
+
+	// A second call to init should not change the value
+	BOOST_CHECK_EQUAL(lazyInit.init([]{ return 42; }), 12);
+}
+
+BOOST_AUTO_TEST_CASE(moved_from_is_empty)
+{
+	{
+		LazyInit<int> lazyInit;
+		{ [[maybe_unused]] auto pilfered = std::move(lazyInit); }
+
+		assertEmpty(std::move(lazyInit));
+	}
+
+	{
+		LazyInit<int> lazyInit;
+		lazyInit.init([]{ return 12; });
+
+		{ [[maybe_unused]] auto pilfered = std::move(lazyInit); }
+
+		assertEmpty(std::move(lazyInit));
+	}
+}
+
+BOOST_AUTO_TEST_CASE(move_constructed_has_same_value_as_original)
+{
+	LazyInit<int> original;
+	original.init([]{ return 12; });
+
+	LazyInit<int> moveConstructed = std::move(original);
+	BOOST_CHECK_EQUAL(valueOf(std::move(moveConstructed)), 12);
+}
 
 BOOST_AUTO_TEST_SUITE_END()