cleaned up code and added correct_outputs.txt for test graphs

graphs/correct_outputs.txt

@@ -0,0 +1,53 @@
+The graphs series of graphs are used to check the code's correctness. Except for internal tiebreaking by the solver, each result is deterministic.
+
+graph1:
+A	B	D
+B	D	D
+
+graph2:
+A	B	D
+B	D	D 
+
+graph3: deals with tiebreaking
+A	C	D
+C	D	D
+
+graph4:
+A	B	D
+B	D	D
+
+graph5:
+A	B	U
+B	D	U
+
+graph6: 
+A	B	U
+B	D	U
+
+graph7: deals with tiebreaking
+A	B	U
+B	D	U
+
+graph8:
+A	B	U
+B	D	U
+
+graph9: 
+A	B	D
+B	D	U
+
+graph10:
+A	B	D
+B	D	D
+
+graph11:
+A	B	U
+B	D	U
+
+graph12:
+A	B	D
+B	D	D
+
+graph13:
+A	B	U
+B	D	U

graphs/graph12/edges.txt

@@ -0,0 +1,4 @@
+A   B   0.9	D
+A   C   0.1	D
+B   D   0.8	D
+C   D   0.2	D

graphs/graph12/sources.txt

@@ -0,0 +1 @@
+A

graphs/graph12/targets.txt

@@ -0,0 +1 @@
+D

graphs/graph13/edges.txt

@@ -0,0 +1,4 @@
+A   B   0.9	U
+A   C   0.1	U
+B   D   0.8	U
+C   D   0.2	U

graphs/graph13/sources.txt

@@ -0,0 +1 @@
+A

graphs/graph13/targets.txt

@@ -0,0 +1 @@
+D

test_minCostFlow.py

@@ -22,7 +22,7 @@
 
 
 print("\ntesting code correctness")
-for i in range (1,12):
+for i in range (1,14):
     print("graph: ",i)
     args = [
     "--edges_file", f"graphs/graph{i}/edges.txt",

tests/correct_outputs.txt

@@ -0,0 +1,31 @@
+The tests series of graphs are used to verify whether the code is executing appropriately depending on distinct edge cases.
+
+test 1: check if unique directed edges are added to directed_dict 
+Output:
+A	B	D
+B	C	D
+
+test2: check if higher edge weight is selected for the same directed edge from the input
+Output:
+A	B	D
+B	D	D
+
+test3: If a directed edge is present in the input and an undirected edge from that edge already exists, the directed edge is prioritized and added to directed_dict and the undirected edge is deleted from undirected_dict.
+A	C	D
+C	D	D
+
+test4: check if unique undirected edges are added to undirected_dict 
+A	B	D
+B	D	D
+
+test5: check that an undirected edge is not added if a directed edge of that edge already exists
+A	B	U
+B	D	U
+
+test6: check if higher edge weight is selected for the same undirected edge from the input
+A	B	U
+B	D	U
+
+test7: check that code still runs and outputs an error message with an empty edges.txt
+A	B	U
+B	D	U