[Chapter13&Inheritance] - Adding tests;Bugs found

- Refactors will be necessary, the interpreter is not working as expected
- Try to execute the tests to check the errors
- It seems some funcionality with the scanner or resolver is not working
- Debugging is necessary.

tests/class_tests.lox

@@ -0,0 +1,35 @@
+class A {
+  method() {
+    print "A method";
+  }
+}
+
+class B < A {
+  method() {
+    print "B method";
+  }
+
+  test() {
+    super.method();
+  }
+}
+
+class C < B {}
+
+C().test();
+
+class Doughnut {
+  cook() {
+    print "Fry until golden brown.";
+  }
+}
+
+class BostonCream < Doughnut {
+  cook() {
+    super.cook();
+    print "Pipe full of custard and coat with chocolate.";
+  }
+}
+
+BostonCream().cook();
+

tests/vars.lox

@@ -0,0 +1,7 @@
+var a = 0;
+a + 1;
+print a + 1;
+a = 2;
+print a + 1;
+var b = 3;
+print a + b