diff --git a/authorize.go b/authorize.go
index b4f03dc..edd6d0b 100644
--- a/authorize.go
+++ b/authorize.go
@@ -31,13 +31,16 @@ func GetAuthorize(key, user string) (AuthorizeResponse, error) {
 	}
 	defer resp.Body.Close()
 
-	result, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		return authorizeResp, errors.Wrap(err, "error in ReadAll")
+	if resp.StatusCode != http.StatusOK {
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return authorizeResp, errors.Wrap(err, "error in ReadAll")
+		}
+		return authorizeResp, errors.Errorf("error body: %s", body)
 	}
 
-	if err := json.Unmarshal(result, &authorizeResp); err != nil {
-		return authorizeResp, errors.Wrap(err, "error in Unmarshal")
+	if err := json.NewDecoder(resp.Body).Decode(&authorizeResp); err != nil {
+		return authorizeResp, errors.Wrap(err, "error in Decode")
 	}
 
 	return authorizeResp, nil
diff --git a/authorize_test.go b/authorize_test.go
index f83e98d..7f42f90 100644
--- a/authorize_test.go
+++ b/authorize_test.go
@@ -1,15 +1,20 @@
 package dozens
 
 import (
-	"errors"
+	"fmt"
 	"net/http"
 	"strings"
 	"testing"
+
+	"github.com/delphinus/go-dozens/endpoint"
+	"github.com/jarcoal/httpmock"
+	"github.com/pkg/errors"
 )
 
 func TestGetAuthorizeWithNewRequestError(t *testing.T) {
 	originalMethodGet := methodGet
 	methodGet = "(" // invalid method
+	defer func() { methodGet = originalMethodGet }()
 
 	_, err := GetAuthorize("", "")
 	result := err.Error()
@@ -18,8 +23,6 @@ func TestGetAuthorizeWithNewRequestError(t *testing.T) {
 	if strings.Index(result, expected) != 0 {
 		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
-
-	methodGet = originalMethodGet
 }
 
 type mockedErrorClient struct{}
@@ -31,6 +34,7 @@ func (c *mockedErrorClient) Do(req *http.Request) (*http.Response, error) {
 func TestGetAuthorizeWithDoError(t *testing.T) {
 	originalClient := httpClient
 	httpClient = &mockedErrorClient{}
+	defer func() { httpClient = originalClient }()
 
 	_, err := GetAuthorize("", "")
 	result := err.Error()
@@ -39,13 +43,12 @@ func TestGetAuthorizeWithDoError(t *testing.T) {
 	if strings.Index(result, expected) != 0 {
 		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
-
-	httpClient = originalClient
 }
 
 func TestGetAuthorizeWithReadAllError(t *testing.T) {
 	originalClient := httpClient
 	httpClient = &mockedClient{}
+	defer func() { httpClient = originalClient }()
 
 	_, err := GetAuthorize("", "")
 	result := err.Error()
@@ -54,6 +57,64 @@ func TestGetAuthorizeWithReadAllError(t *testing.T) {
 	if strings.Index(result, expected) != 0 {
 		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
+}
+
+func TestGetAuthorizeWithErrorResponse(t *testing.T) {
+	httpmock.Activate()
+	defer httpmock.DeactivateAndReset()
+
+	url := endpoint.Authorize().String()
+	validStatus := http.StatusOK
+	invalidJSON := "("
+	httpmock.RegisterResponder(methodGet, url, httpmock.NewStringResponder(validStatus, invalidJSON))
+
+	_, err := GetAuthorize("", "")
+	result := err.Error()
+
+	expected := "error in Decode"
+	if strings.Index(result, expected) != 0 {
+		t.Errorf("expected '%s', but got '%s'", expected, result)
+	}
+}
+
+func TestGetAuthorizeStatusNotOK(t *testing.T) {
+	httpmock.Activate()
+	defer httpmock.DeactivateAndReset()
 
-	httpClient = originalClient
+	url := endpoint.Authorize().String()
+	invalidStatus := http.StatusBadRequest
+	mockStr := "as a mock"
+
+	httpmock.RegisterResponder(methodGet, url, httpmock.NewStringResponder(invalidStatus, mockStr))
+
+	_, err := GetAuthorize("", "")
+	result := errors.Cause(err).Error()
+
+	expected := fmt.Sprintf("error body: %s", mockStr)
+	if result != expected {
+		t.Errorf("expected '%s',but got '%s'", expected, result)
+	}
+}
+
+func TestGetAuthorizeValidResponse(t *testing.T) {
+	httpmock.Activate()
+	defer httpmock.DeactivateAndReset()
+
+	url := endpoint.Authorize().String()
+	validStatus := http.StatusOK
+	validResp := AuthorizeResponse{"hoge"}
+
+	responder, _ := httpmock.NewJsonResponder(validStatus, &validResp)
+	httpmock.RegisterResponder(methodGet, url, responder)
+
+	resp, err := GetAuthorize("", "")
+	if err != nil {
+		t.Errorf("error got: %v", err)
+	}
+
+	result := resp.AuthToken
+	expected := validResp.AuthToken
+	if result != expected {
+		t.Errorf("expected '%s', but got '%s'", expected, result)
+	}
 }
diff --git a/record_test.go b/record_test.go
index 2207ae6..a85b3c8 100644
--- a/record_test.go
+++ b/record_test.go
@@ -24,6 +24,7 @@ func TestDoRecordRequestInvalidRequest(t *testing.T) {
 func TestDoRecordRequestIOError(t *testing.T) {
 	originalClient := httpClient
 	httpClient = &mockedClient{}
+	defer func() { httpClient = originalClient }()
 
 	_, err := doRecordRequest(&http.Request{})
 	result := err.Error()
@@ -32,8 +33,6 @@ func TestDoRecordRequestIOError(t *testing.T) {
 	if strings.Index(result, expected) != 0 {
 		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
-
-	httpClient = originalClient
 }
 
 func TestDoRecordRequestStatusNotOK(t *testing.T) {
diff --git a/request_test.go b/request_test.go
index 916ca00..d4f697c 100644
--- a/request_test.go
+++ b/request_test.go
@@ -43,6 +43,7 @@ func TestMakeDelete(t *testing.T) {
 func TestMakeGetWithError(t *testing.T) {
 	originalMethodGet := methodGet
 	methodGet = "(" // invalid method rune
+	defer func() { methodGet = originalMethodGet }()
 
 	p := endpoint.Endpoint{
 		Base:  &url.URL{},
@@ -51,6 +52,4 @@ func TestMakeGetWithError(t *testing.T) {
 	if _, err := MakeGet("", p); err == nil {
 		t.Errorf("MakeGet did not return error")
 	}
-
-	methodGet = originalMethodGet
 }
diff --git a/zone_test.go b/zone_test.go
index d275d95..9da8a93 100644
--- a/zone_test.go
+++ b/zone_test.go
@@ -40,6 +40,7 @@ func (c *mockedClient) Do(req *http.Request) (*http.Response, error) {
 func TestDoZoneRequestIOError(t *testing.T) {
 	originalClient := httpClient
 	httpClient = &mockedClient{}
+	defer func() { httpClient = originalClient }()
 
 	_, err := doZoneRequest(&http.Request{})
 	result := err.Error()
@@ -48,28 +49,25 @@ func TestDoZoneRequestIOError(t *testing.T) {
 	if strings.Index(result, expected) != 0 {
 		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
-
-	httpClient = originalClient
 }
 
 func TestDoZoneRequestStatusNotOK(t *testing.T) {
 	httpmock.Activate()
 	defer httpmock.DeactivateAndReset()
 
-	method := "GET"
 	hogeURL := "http://hoge.com"
 	mockStr := "as a mock"
 	badStatus := http.StatusBadRequest
 
-	httpmock.RegisterResponder(method, hogeURL, httpmock.NewStringResponder(badStatus, mockStr))
-	req, _ := http.NewRequest(method, hogeURL, nil)
+	httpmock.RegisterResponder(methodGet, hogeURL, httpmock.NewStringResponder(badStatus, mockStr))
+	req, _ := http.NewRequest(methodGet, hogeURL, nil)
 
 	_, err := doZoneRequest(req)
 	result := errors.Cause(err).Error()
 
 	expected := fmt.Sprintf("error body: %s", mockStr)
 	if result != expected {
-		t.Errorf("expected '%s', bug got '%s'", expected, result)
+		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
 }
 
@@ -89,7 +87,7 @@ func TestDoZoneRequestBadJSON(t *testing.T) {
 
 	expected := "error in Decode"
 	if strings.Index(result, expected) != 0 {
-		t.Errorf("expected '%s', bug got '%s'", expected, result)
+		t.Errorf("expected '%s', but got '%s'", expected, result)
 	}
 }