tests: testing tools/diff.py

tools/tests/diff-two-files-c.should_get

+!LAUNCH: python ../diff.py ../../data/results-two-clones-1-2.vidjil ../../data/results-two-clones-1-3.vidjil -c
+
+$ Clone id-1 is a common clone, with a different number of reads 
+1:id-1 .* 800 .* 300
+
+$ Clone id-2 is not a common clone
+0:id-2
+
+$ Clone id-3 is not a common clone
+0:id-3
+

tools/tests/diff-two-files.should_get

+!LAUNCH: python ../diff.py ../../data/results-two-clones-1-2.vidjil ../../data/results-two-clones-1-3.vidjil
+
+$ Clone id-1 has a different number of reads 
+1:Not the same number or reads: id-1
+
+$ Clone id-2 is not in the second file
+1:[-] .* Clone not present: .* id-2
+
+$ Clone id-3 is not in the first file
+1:[+] .* Clone not present: .* id-3