Add tests

Author: mattn

test/test1.ok

@@ -46,3 +46,8 @@
 (echo (subscript x 0) (subscript x y))
 (echo (slice x 1 2) (slice x 1 nil) (slice x nil 2) (slice x nil nil))
 (echo (dot x y) (dot (dot x y) z))
+(let = a 1)
+(let += a 2)
+(let *= a 3)
+(let /= a 4)
+(let %= a 5)

test/test1.vim

@@ -51,3 +51,8 @@ echo {} {"x":"y"} {"x":"y","z":"w",}
 echo x[0] x[y]
 echo x[1:2] x[1:] x[:2] x[:]
 echo x.y x.y.z
+let a = 1
+let a += 2
+let a *= 3
+let a /= 4
+let a %= 5