add unit tests

Signed-off-by: Bugen Zhao <[email protected]>

e2e_test/batch/functions/vnode.slt.part

@@ -0,0 +1,33 @@
+query error Function `rw_vnode` takes at least 2 arguments (0 given)
+select rw_vnode();
+
+query error Function `rw_vnode` takes at least 2 arguments (1 given)
+select rw_vnode(256);
+
+query I
+select rw_vnode(256, 114, 514);
+----
+97
+
+query I
+select rw_vnode(4096, 114, 514);
+----
+1377
+
+query error the first argument (vnode count) must not be NULL
+select rw_vnode(NULL, 114, 514);
+
+statement ok
+create table vnodes (vnode int);
+
+statement ok
+insert into vnodes values (256), (4096);
+
+statement ok
+flush;
+
+query error the first argument (vnode count) must be a constant
+select rw_vnode(vnode, 114, 514) from vnodes;
+
+statement ok
+drop table vnodes;