move plumbing from top level package to plumbing (#183)

* plumbing: rename Object -> EncodedObject.

* plumbing/storer: rename ObjectStorer -> EncodedObjectStorer.

* move difftree to plumbing/difftree.

* move diff -> utils/diff

* make Object/Tag/Blob/Tree/Commit/File depend on storer.

* Object and its implementations now depend only on
  storer.EncodedObjectStorer, not git.Repository.
* Tests are decoupled accordingly.

* move Object/Commit/File/Tag/Tree to plumbing/object.

* move Object/Commit/File/Tag/Tree to plumbing/object.
* move checkClose to utils/ioutil.

* move RevListObjects to plumbing/revlist.Objects.

* move DiffTree to plumbing/difftree package.

* rename files with plural nouns to singular

* plumbing/object: add GetBlob/GetCommit/GetTag/GetTree.

1 files changed, 68 insertions, 0 deletions

diff --git a/plumbing/difftree/internal/merkletrie/node_test.go b/plumbing/difftree/internal/merkletrie/node_test.go
new file mode 100644
index 0000000..1622952
--- /dev/null
+++ b/plumbing/difftree/internal/merkletrie/node_test.go
@@ -0,0 +1,68 @@
+package merkletrie
+
+import (
+	"testing"
+
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type NodeSuite struct{}
+
+var _ = Suite(&NodeSuite{})
+
+func (s *NodeSuite) TestHash(c *C) {
+	n := newNode([]byte("the_hash"), "the_key", []*node{})
+
+	expected := []byte("the_hash")
+	c.Assert(expected, DeepEquals, n.Hash())
+}
+
+func (s *NodeSuite) TestKey(c *C) {
+	n := newNode([]byte("the_hash"), "the_key", []*node{})
+
+	expected := "the_key"
+	c.Assert(expected, Equals, n.Key())
+}
+
+func (s *NodeSuite) TestNoChildren(c *C) {
+	n := newNode([]byte{}, "", []*node{})
+
+	expectedNumChildren := 0
+	c.Assert(n.NumChildren(), Equals, expectedNumChildren)
+
+	expectedChildren := []Noder{}
+	c.Assert(n.Children(), DeepEquals, expectedChildren)
+}
+
+func (s *NodeSuite) TestOneChild(c *C) {
+	child := newNode([]byte("child"), "child", []*node{})
+	parent := newNode([]byte("parent"), "parent", []*node{child})
+
+	expectedNumChildren := 1
+	c.Assert(parent.NumChildren(), Equals, expectedNumChildren)
+
+	expectedChildren := []Noder{Noder(child)}
+	c.Assert(parent.Children(), DeepEquals, expectedChildren)
+}
+
+func (s *NodeSuite) TestManyChildren(c *C) {
+	child0 := newNode([]byte("child0"), "child0", []*node{})
+	child1 := newNode([]byte("child1"), "child1", []*node{})
+	child2 := newNode([]byte("child2"), "child2", []*node{})
+	child3 := newNode([]byte("child3"), "child3", []*node{})
+	// children are added unsorted.
+	parent := newNode([]byte("parent"), "parent", []*node{child1, child3, child0, child2})
+
+	expectedNumChildren := 4
+	c.Assert(parent.NumChildren(), Equals, expectedNumChildren)
+
+	expectedChildren := []Noder{ // sorted alphabetically by key
+		Noder(child3),
+		Noder(child2),
+		Noder(child1),
+		Noder(child0),
+	}
+	c.Assert(parent.Children(), DeepEquals, expectedChildren)
+}