moved walk/same into a package, and added a true test file

ebt/ebt.go

@@ -0,0 +1,38 @@
+package ebt
+
+import (
+	"code.google.com/p/go-tour/tree"
+)
+
+// Walk walks the tree t sending all values
+// from the tree to the channel ch.
+func Walk(t *tree.Tree, ch chan int) {
+	// do it as a nested closure so that I can control the call to close so 
+	// that I can use the range-based forloop in main.main
+	var walk func(t *tree.Tree)
+	walk = func(t *tree.Tree) {
+		if t != nil {
+			walk(t.Left)
+			ch <- t.Value
+			walk(t.Right)
+		}
+	}
+	walk(t)
+	close(ch)
+}
+
+// Same determines whether the trees
+// t1 and t2 contain the same values.
+func Same(t1, t2 *tree.Tree) bool {
+	ch1 := make(chan int)
+	ch2 := make(chan int)
+	go Walk(t1, ch1)
+	go Walk(t2, ch2)
+	for i := range ch1 {
+		if i != <-ch2 {
+			return false
+		}
+	}
+	return true
+}
+

ebt/ebt_test.go

@@ -0,0 +1,18 @@
+package ebt
+
+import (
+	"code.google.com/p/go-tour/tree"
+	"testing"
+)
+
+func TestSameTrees(t *testing.T) {
+	if !Same(tree.New(1), tree.New(1)) {
+		t.Error("Trees should have been the same ...")
+	}
+}
+
+func TestDifferentTrees(t *testing.T) {
+	if Same(tree.New(1), tree.New(2)) {
+		t.Error("Trees should have been the different ...")
+	}
+}