moved tests directory

tests_dir/left_join.result

@@ -0,0 +1,18 @@
+id,name,chief,age,skill
+2,john,1,30,C
+7,alia,1,28,C
+4,eve,0,25,C++
+6,paul,4,30,---
+5,duncan,4,30,Perl
+1,carl,0,20,C++
+7,alia,1,28,PHP
+4,eve,0,25,C
+7,alia,1,28,Python
+3,dean,1,33,C++
+1,carl,0,20,Python
+2,john,1,30,PHP
+0,jack,0,22,Python
+0,jack,0,22,C
+1,carl,0,20,System Admin
+4,eve,0,25,Perl
+5,duncan,4,30,C