Improve the GameEngine test.

tests/game_engine.cpp

@@ -41,10 +41,31 @@ TEST_CASE("brainfuck loop test", "[brainfuck]") {
   REQUIRE(output == expected);
 }
 
-TEST_CASE("game engine can start and take hit", "[brainfuck]") {
+TEST_CASE("game engine can start and take hit", "[game_engine]") {
   // test fails on purpose right now
   GameEngine game{4};
   string err{"error"};
+  game.start_round();
   game.hit(err);
+  game.end_round();
   REQUIRE(game.is_dead() == true);
 }
+
+TEST_CASE("", "[game_engine]") {
+  // test fails on purpose right now
+  GameEngine game{100};
+  string err{"error"};
+
+  game.start_round();
+  game.hit(err);
+  game.end_round();
+
+  REQUIRE(game.hit_points < 100);
+  REQUIRE(game.is_dead() == false);
+
+  game.start_round();
+  game.end_round();
+
+  REQUIRE(game.hit_points == 100);
+  REQUIRE(game.is_dead() == false);
+}