Move engine-api client package

This moves the engine-api client package to `/docker/docker/client`.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

plugin_list_test.go

@@ -0,0 +1,61 @@
+// +build experimental
+
+package client
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/docker/docker/api/types"
+	"golang.org/x/net/context"
+)
+
+func TestPluginListError(t *testing.T) {
+	client := &Client{
+		transport: newMockClient(nil, errorMock(http.StatusInternalServerError, "Server error")),
+	}
+
+	_, err := client.PluginList(context.Background())
+	if err == nil || err.Error() != "Error response from daemon: Server error" {
+		t.Fatalf("expected a Server Error, got %v", err)
+	}
+}
+
+func TestPluginList(t *testing.T) {
+	expectedURL := "/plugins"
+	client := &Client{
+		transport: newMockClient(nil, func(req *http.Request) (*http.Response, error) {
+			if !strings.HasPrefix(req.URL.Path, expectedURL) {
+				return nil, fmt.Errorf("Expected URL '%s', got '%s'", expectedURL, req.URL)
+			}
+			content, err := json.Marshal([]*types.Plugin{
+				{
+					ID: "plugin_id1",
+				},
+				{
+					ID: "plugin_id2",
+				},
+			})
+			if err != nil {
+				return nil, err
+			}
+			return &http.Response{
+				StatusCode: http.StatusOK,
+				Body:       ioutil.NopCloser(bytes.NewReader(content)),
+			}, nil
+		}),
+	}
+
+	plugins, err := client.PluginList(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(plugins) != 2 {
+		t.Fatalf("expected 2 plugins, got %v", plugins)
+	}
+}