@@ -212,18 +212,11 @@ func (cli *Client) getAPIPath(p string, query url.Values) string {

 	var apiPath string

 	if cli.version != "" {

 		v := strings.TrimPrefix(cli.version, "v")

-		apiPath = path.Join(cli.basePath, "/v"+v+p)

+		apiPath = path.Join(cli.basePath, "/v"+v, p)

 	} else {

 		apiPath = path.Join(cli.basePath, p)

 	}

-

-	u := &url.URL{

-		Path: apiPath,

-	}

-	if len(query) > 0 {

-		u.RawQuery = query.Encode()

-	}

-	return u.String()

+	return (&url.URL{Path: apiPath, RawQuery: query.Encode()}).String()

 }

 // ClientVersion returns the API version used by this client.

@@ -105,11 +105,11 @@ func TestNewEnvClient(t *testing.T) {

 }

 func TestGetAPIPath(t *testing.T) {

-	cases := []struct {

-		v string

-		p string

-		q url.Values

-		e string

+	testcases := []struct {

+		version  string

+		path     string

+		query    url.Values

+		expected string

 	}{

 		{"", "/containers/json", nil, "/containers/json"},

 		{"", "/containers/json", url.Values{}, "/containers/json"},

@@ -123,16 +123,10 @@ func TestGetAPIPath(t *testing.T) {

 		{"v1.22", "/networks/kiwl$%^", nil, "/v1.22/networks/kiwl$%25%5E"},

 	}

-	for _, cs := range cases {

-		c, err := NewClient("unix:///var/run/docker.sock", cs.v, nil, nil)

-		if err != nil {

-			t.Fatal(err)

-		}

-		g := c.getAPIPath(cs.p, cs.q)

-		assert.Equal(t, g, cs.e)

-

-		err = c.Close()

-		assert.NoError(t, err)

+	for _, testcase := range testcases {

+		c := Client{version: testcase.version, basePath: "/"}

+		actual := c.getAPIPath(testcase.path, testcase.query)

+		assert.Equal(t, actual, testcase.expected)

 	}

 }

@@ -5,6 +5,7 @@ import (

 	"encoding/json"

 	"io/ioutil"

 	"net/http"

+	"path"

 	"github.com/docker/docker/api/types"

 	"golang.org/x/net/context"

@@ -18,8 +19,15 @@ func (cli *Client) VolumeInspect(ctx context.Context, volumeID string) (types.Vo

 // VolumeInspectWithRaw returns the information about a specific volume in the docker host and its raw representation

 func (cli *Client) VolumeInspectWithRaw(ctx context.Context, volumeID string) (types.Volume, []byte, error) {

+	// The empty ID needs to be handled here because with an empty ID the

+	// request url will not contain a trailing / which calls the volume list API

+	// instead of volume inspect

+	if volumeID == "" {

+		return types.Volume{}, nil, volumeNotFoundError{volumeID}

+	}

+

 	var volume types.Volume

-	resp, err := cli.get(ctx, "/volumes/"+volumeID, nil, nil)

+	resp, err := cli.get(ctx, path.Join("/volumes", volumeID), nil, nil)

 	if err != nil {

 		if resp.statusCode == http.StatusNotFound {

 			return volume, nil, volumeNotFoundError{volumeID}

@@ -10,6 +10,9 @@ import (

 	"testing"

 	"github.com/docker/docker/api/types"

+	"github.com/docker/docker/internal/testutil"

+	"github.com/stretchr/testify/assert"

+	"github.com/stretchr/testify/require"

 	"golang.org/x/net/context"

 )

@@ -19,9 +22,7 @@ func TestVolumeInspectError(t *testing.T) {

 	}

 	_, err := client.VolumeInspect(context.Background(), "nothing")

-	if err == nil || err.Error() != "Error response from daemon: Server error" {

-		t.Fatalf("expected a Server Error, got %v", err)

-	}

+	testutil.ErrorContains(t, err, "Error response from daemon: Server error")

 }

 func TestVolumeInspectNotFound(t *testing.T) {

@@ -30,13 +31,34 @@ func TestVolumeInspectNotFound(t *testing.T) {

 	}

 	_, err := client.VolumeInspect(context.Background(), "unknown")

-	if err == nil || !IsErrVolumeNotFound(err) {

-		t.Fatalf("expected a volumeNotFound error, got %v", err)

+	assert.True(t, IsErrNotFound(err))

+}

+

+func TestVolumeInspectWithEmptyID(t *testing.T) {

+	expectedURL := "/volumes/"

+

+	client := &Client{

+		client: newMockClient(func(req *http.Request) (*http.Response, error) {

+			assert.Equal(t, req.URL.Path, expectedURL)

+			return &http.Response{

+				StatusCode: http.StatusNotFound,

+				Body:       ioutil.NopCloser(bytes.NewReader(nil)),

+			}, nil

+		}),

 	}

+	_, err := client.VolumeInspect(context.Background(), "")

+	testutil.ErrorContains(t, err, "No such volume: ")

+

 }

 func TestVolumeInspect(t *testing.T) {

 	expectedURL := "/volumes/volume_id"

+	expected := types.Volume{

+		Name:       "name",

+		Driver:     "driver",

+		Mountpoint: "mountpoint",

+	}

+

 	client := &Client{

 		client: newMockClient(func(req *http.Request) (*http.Response, error) {

 			if !strings.HasPrefix(req.URL.Path, expectedURL) {

@@ -45,11 +67,7 @@ func TestVolumeInspect(t *testing.T) {

 			if req.Method != "GET" {

 				return nil, fmt.Errorf("expected GET method, got %s", req.Method)

 			}

-			content, err := json.Marshal(types.Volume{

-				Name:       "name",

-				Driver:     "driver",

-				Mountpoint: "mountpoint",

-			})

+			content, err := json.Marshal(expected)

 			if err != nil {

 				return nil, err

 			}

@@ -60,17 +78,7 @@ func TestVolumeInspect(t *testing.T) {

 		}),

 	}

-	v, err := client.VolumeInspect(context.Background(), "volume_id")

-	if err != nil {

-		t.Fatal(err)

-	}

-	if v.Name != "name" {

-		t.Fatalf("expected `name`, got %s", v.Name)

-	}

-	if v.Driver != "driver" {

-		t.Fatalf("expected `driver`, got %s", v.Driver)

-	}

-	if v.Mountpoint != "mountpoint" {

-		t.Fatalf("expected `mountpoint`, got %s", v.Mountpoint)

-	}

+	volume, err := client.VolumeInspect(context.Background(), "volume_id")

+	require.NoError(t, err)

+	assert.Equal(t, expected, volume)

 }