Add test for Bug #902091 (Positioned iteration over a multipart index doesn't work).

test/box_big/lua.result

@@ -21,6 +21,45 @@ An error occurred: ER_KEY_CARDINALITY, 'Key cardinality 3 is greater than index
 call box.delete(1, 'brave')
 Found 1 tuple:
 ['brave', 'new', 'world']
+#
+# A test case for Bug #902091
+# "Positioned iteration over a multipart index doesn't work"
+# https://bugs.launchpad.net/tarantool/+bug/902091
+#
+insert into t1 values ('item 1', 'alabama', 'song')
+Insert OK, 1 row affected
+insert into t1 values ('item 2', 'california', 'dreaming')
+Insert OK, 1 row affected
+insert into t1 values ('item 3', 'california', 'uber alles')
+Insert OK, 1 row affected
+insert into t1 values ('item 4', 'georgia', 'on my mind')
+Insert OK, 1 row affected
+lua iter, tuple = box.space[1].index[1]:next('california')
+---
+...
+lua tuple
+---
+ - 'item 2': {'california', 'dreaming'}
+...
+lua iter, tuple = box.space[1].index[1]:next(iter)
+---
+...
+lua tuple
+---
+ - 'item 3': {'california', 'uber alles'}
+...
+call box.delete(1, 'item 1')
+Found 1 tuple:
+['item 1', 'alabama', 1735290739]
+call box.delete(1, 'item 2')
+Found 1 tuple:
+['item 2', 'california', 'dreaming']
+call box.delete(1, 'item 3')
+Found 1 tuple:
+['item 3', 'california', 'uber alles']
+call box.delete(1, 'item 4')
+Found 1 tuple:
+['item 4', 'georgia', 'on my mind']
 insert into t5 values ('01234567', 'new', 'world')
 Insert OK, 1 row affected
 insert into t5 values ('00000000', 'of', 'puppets')

test/box_big/lua.test

@@ -11,6 +11,24 @@ print """#
 exec sql "call box.select(1, 1, 'new', 'world', 'order')"
 exec sql "call box.delete(1, 'brave')"
 
+print """#
+# A test case for Bug #902091
+# "Positioned iteration over a multipart index doesn't work"
+# https://bugs.launchpad.net/tarantool/+bug/902091
+#"""
+exec sql "insert into t1 values ('item 1', 'alabama', 'song')"
+exec sql "insert into t1 values ('item 2', 'california', 'dreaming')"
+exec sql "insert into t1 values ('item 3', 'california', 'uber alles')"
+exec sql "insert into t1 values ('item 4', 'georgia', 'on my mind')"
+exec admin "lua iter, tuple = box.space[1].index[1]:next('california')"
+exec admin "lua tuple"
+exec admin "lua iter, tuple = box.space[1].index[1]:next(iter)"
+exec admin "lua tuple"
+exec sql "call box.delete(1, 'item 1')"
+exec sql "call box.delete(1, 'item 2')"
+exec sql "call box.delete(1, 'item 3')"
+exec sql "call box.delete(1, 'item 4')"
+
 #
 # Check range scan over multipart keys
 #