Added missing tests for coverage

Author: cschreib

tests/data/errors.txt

@@ -7676,6 +7676,20 @@ error: unknown unary operator '>'
 obj[#]
     ^
 error: unexpected character
+(1+'').a
+^~~~~~
+error: no overload of '+' accepts the provided types (int,string)
+note: available overloads:
+        +(string,string)
+        +(float,float)
+        +(float,int)
+        +(int,float)
+        +(int,int)
+        +(float)
+        +(int)
+''.a
+^~
+error: expected object, got string
 '"
 ^~
 error: unterminated string

tests/src/object.cpp

@@ -64,6 +64,8 @@ TEST_CASE("object access", "[object]") {
         CHECK_ERROR("obj[(]", vars);
         CHECK_ERROR("obj[>]", vars);
         CHECK_ERROR("obj[#]", vars);
+        CHECK_ERROR("(1+'').a", vars);
+        CHECK_ERROR("''.a", vars);
     }
 
     SECTION("good") {