Changed test layout and refactorized some tests for OutputPort

Changed test layout and refactored some test cases according to test plan. The tests work locally but the pipeline seems to fail?

test/fixtures/operation_tree.py

@@ -19,9 +19,9 @@ def create_operation(_type, dest_oper, index, **kwargs):
 def operation_tree():
     """
     Return a addition operation connected with 2 constants.
-    >---C---+
-            ---A
-    >---C---+
+    ---C---+
+           ---A
+    ---C---+
     """
     add_oper = Addition()
     create_operation(Constant, add_oper, 0, value=2)
@@ -32,13 +32,13 @@ def operation_tree():
 def large_operation_tree():
     """
     Return a constant operation connected with a large operation tree with 3 other constants and 3 additions.
-    >---C---+
-            ---A---+
-    >---C---+      |
-                   +---A
-    >---C---+      |
-            ---A---+
-    >---C---+
+    ---C---+
+           ---A---+
+    ---C---+      |
+                  +---A
+    ---C---+      |
+           ---A---+
+    ---C---+
     """
     add_oper = Addition()
     add_oper_2 = Addition()