Better testing reveals broken delete...

The latest commit on GitHub has an updated test implementation. It's a big improvement over what I had before because it uses Go's map type as a reference implementation. First I created an interface "TreeLike" that defines the basic operations on a tree:

type Treelike interface {
Insert(uint64, interface{})
Fetch(uint64) interface{}
Delete(uint64)
Iterate() chan uint64
}

I know Iterate() is basically useless, it's still a work in progress. TreeLike is already implemented by Btree. Now I make a struct that implements checking. 

type BtreeTest struct {

test *testing.T

tree Treelike 

reference map[uint64] interface{}

}

The class contains a test so that I can testing.T.Fail() when a problem is detected. The TreeLike is kept in sync with the map[] by implementing methods that operate on both structures. This is the implementation of Insert():

func (self *BtreeTest) Insert(key uint64, value interface{}) {

self.reference[key] = value

self.tree.Insert(key, value)

}

The Insert() function does no checking. The Delete() function does:

func (self *BtreeTest) Delete(key uint64) {

delete(self.reference, key)

self.tree.Delete(key)

verify := self.tree.Fetch(key) 

if (verify != nil) {

self.test.Fail()

}

}

The struct BtreeTest itself implements TreeLike so any code that requires TreeLike can be easily instrumented to be testing code. Thanks to that I found a serious bug in Delete(). My delete function fails to delete values that are not stored in leaf nodes. I'm fixing it.