Move engine-api client package

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

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

client/plugin_inspect_test.go

@@ -0,0 +1,56 @@
+// +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 TestPluginInspectError(t *testing.T) {
+	client := &Client{
+		transport: newMockClient(nil, errorMock(http.StatusInternalServerError, "Server error")),
+	}
+
+	_, _, err := client.PluginInspectWithRaw(context.Background(), "nothing")
+	if err == nil || err.Error() != "Error response from daemon: Server error" {
+		t.Fatalf("expected a Server Error, got %v", err)
+	}
+}
+
+func TestPluginInspect(t *testing.T) {
+	expectedURL := "/plugins/plugin_name"
+	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_id",
+			})
+			if err != nil {
+				return nil, err
+			}
+			return &http.Response{
+				StatusCode: http.StatusOK,
+				Body:       ioutil.NopCloser(bytes.NewReader(content)),
+			}, nil
+		}),
+	}
+
+	pluginInspect, _, err := client.PluginInspectWithRaw(context.Background(), "plugin_name")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if pluginInspect.ID != "plugin_id" {
+		t.Fatalf("expected `plugin_id`, got %s", pluginInspect.ID)
+	}
+}