transport: create Client interface (#132)

* plumbing: move plumbing/client package to plumbing/transport.

* transport: create Client interface.

* A Client can instantiate any client transport service.
* InstallProtocol installs a Client for a given protocol,
  instead of just a UploadPackService.
* A Client can open a session for fetch-pack or send-pack
  for a specific Endpoint.
* Adapt ssh and http clients to the new client interface.

* updated doc

1 files changed, 73 insertions, 0 deletions

diff --git a/plumbing/transport/client/client_test.go b/plumbing/transport/client/client_test.go
new file mode 100644
index 0000000..90bad57
--- /dev/null
+++ b/plumbing/transport/client/client_test.go
@@ -0,0 +1,73 @@
+package client
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+
+	"gopkg.in/src-d/go-git.v4/plumbing/transport"
+
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type ClientSuite struct{}
+
+var _ = Suite(&ClientSuite{})
+
+func (s *ClientSuite) TestNewClientHTTP(c *C) {
+	e, err := transport.NewEndpoint("http://github.com/src-d/go-git")
+	c.Assert(err, IsNil)
+
+	output, err := NewClient(e)
+	c.Assert(err, IsNil)
+	c.Assert(typeAsString(output), Equals, "*http.Client")
+
+	e, err = transport.NewEndpoint("https://github.com/src-d/go-git")
+	c.Assert(err, IsNil)
+
+	output, err = NewClient(e)
+	c.Assert(err, IsNil)
+	c.Assert(typeAsString(output), Equals, "*http.Client")
+}
+
+func (s *ClientSuite) TestNewClientSSH(c *C) {
+	e, err := transport.NewEndpoint("ssh://github.com/src-d/go-git")
+	c.Assert(err, IsNil)
+
+	output, err := NewClient(e)
+	c.Assert(err, IsNil)
+	c.Assert(typeAsString(output), Equals, "*ssh.Client")
+}
+
+func (s *ClientSuite) TestNewClientUnknown(c *C) {
+	e, err := transport.NewEndpoint("unknown://github.com/src-d/go-git")
+	c.Assert(err, IsNil)
+
+	_, err = NewClient(e)
+	c.Assert(err, NotNil)
+}
+
+func (s *ClientSuite) TestInstallProtocol(c *C) {
+	InstallProtocol("newscheme", &dummyClient{})
+	c.Assert(Protocols["newscheme"], NotNil)
+}
+
+type dummyClient struct {
+	*http.Client
+}
+
+func (*dummyClient) NewFetchPackSession(transport.Endpoint) (
+	transport.FetchPackSession, error) {
+	return nil, nil
+}
+
+func (*dummyClient) NewSendPackSession(transport.Endpoint) (
+	transport.SendPackSession, error) {
+	return nil, nil
+}
+
+func typeAsString(v interface{}) string {
+	return fmt.Sprintf("%T", v)
+}