Add diff and status output in tester

.gitignore

@@ -1,6 +1,7 @@
 # ---> Lab
 *.tab.*
 lex*
+ans.out.txt
 
 # ---> C
 # Object files

test.sh

@@ -1,6 +1,15 @@
 #!/bin/sh
 
-echo "Program output :"
-cat test.txt | ./eval.out
-echo "Expected output :"
-cat ans.txt
+echo "Executing tests ..."
+cat test.txt | ./eval.out > ans.out.txt
+echo "Done."
+echo "Show diff ..."
+diff ans.txt ans.out.txt
+
+# Test equality
+if [ $status ]
+then
+	echo 'All tests are OK.'
+else
+	echo 'Failure !!!'
+fi