diff --git a/graphql.go b/graphql.go
index 05c29b7..a8ea9c0 100644
--- a/graphql.go
+++ b/graphql.go
@@ -35,17 +35,17 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/pkg/errors"
 	"io"
 	"mime/multipart"
 	"net/http"
-
-	"github.com/pkg/errors"
+	"strings"
 )
 
 // Client is a client for interacting with a GraphQL API.
 type Client struct {
 	endpoint         string
-	httpClient       *http.Client
+	httpClient       httpDoer
 	useMultipartForm bool
 
 	// closeReq will close the request body immediately allowing for reuse of client
@@ -143,9 +143,9 @@ func (c *Client) runWithJSON(ctx context.Context, req *Request, resp interface{}
 		}
 		return errors.Wrap(err, "decoding response")
 	}
+
 	if len(gr.Errors) > 0 {
-		// return first error
-		return gr.Errors[0]
+		return gr.Errors
 	}
 	return nil
 }
@@ -214,9 +214,9 @@ func (c *Client) runWithPostFields(ctx context.Context, req *Request, resp inter
 		}
 		return errors.Wrap(err, "decoding response")
 	}
+
 	if len(gr.Errors) > 0 {
-		// return first error
-		return gr.Errors[0]
+		return gr.Errors
 	}
 	return nil
 }
@@ -224,7 +224,7 @@ func (c *Client) runWithPostFields(ctx context.Context, req *Request, resp inter
 // WithHTTPClient specifies the underlying http.Client to use when
 // making requests.
 //  NewClient(endpoint, WithHTTPClient(specificHTTPClient))
-func WithHTTPClient(httpclient *http.Client) ClientOption {
+func WithHTTPClient(httpclient httpDoer) ClientOption {
 	return func(client *Client) {
 		client.httpClient = httpclient
 	}
@@ -249,8 +249,25 @@ func ImmediatelyCloseReqBody() ClientOption {
 // modify the behaviour of the Client.
 type ClientOption func(*Client)
 
+type graphErrs []graphErr
+
+func (e graphErrs) Error() string {
+	if len(e) == 1 {
+		return fmt.Sprintf("1 error occurred:\n\t* %s\n\n", e[0])
+	}
+
+	points := make([]string, len(e))
+	for i, err := range e {
+		points[i] = fmt.Sprintf("* %s", err)
+	}
+
+	return fmt.Sprintf(
+		"%d errors occurred:\n\t%s\n\n",
+		len(e), strings.Join(points, "\n\t"))
+}
+
 type graphErr struct {
-	Message string
+	Message string `json:"message"`
 }
 
 func (e graphErr) Error() string {
@@ -258,8 +275,8 @@ func (e graphErr) Error() string {
 }
 
 type graphResponse struct {
-	Data   interface{}
-	Errors []graphErr
+	Data   interface{} `json:"data"`
+	Errors graphErrs   `json:"errors"`
 }
 
 // Request is a GraphQL request.
@@ -322,3 +339,7 @@ type File struct {
 	Name  string
 	R     io.Reader
 }
+
+type httpDoer interface {
+	Do(req *http.Request) (*http.Response, error)
+}
diff --git a/graphql_json_test.go b/graphql_json_test.go
index a973d2d..17800d5 100644
--- a/graphql_json_test.go
+++ b/graphql_json_test.go
@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 	"time"
 
@@ -92,7 +93,8 @@ func TestDoJSONBadRequestErr(t *testing.T) {
 	var responseData map[string]interface{}
 	err := client.Run(ctx, &Request{q: "query {}"}, &responseData)
 	is.Equal(calls, 1) // calls
-	is.Equal(err.Error(), "graphql: miscellaneous message as to why the the request was bad")
+	is.Equal(len(err.(graphErrs)), 1)
+	is.True(strings.Contains(err.Error(), "graphql: miscellaneous message as to why the the request was bad"))
 }
 
 func TestQueryJSON(t *testing.T) {
diff --git a/graphql_multipart_test.go b/graphql_multipart_test.go
index b52da2c..ce31860 100644
--- a/graphql_multipart_test.go
+++ b/graphql_multipart_test.go
@@ -114,7 +114,7 @@ func TestDoErr(t *testing.T) {
 	var responseData map[string]interface{}
 	err := client.Run(ctx, &Request{q: "query {}"}, &responseData)
 	is.True(err != nil)
-	is.Equal(err.Error(), "graphql: Something went wrong")
+	is.True(strings.Contains(err.Error(), "graphql: Something went wrong"))
 }
 
 func TestDoServerErr(t *testing.T) {
@@ -164,7 +164,7 @@ func TestDoBadRequestErr(t *testing.T) {
 	defer cancel()
 	var responseData map[string]interface{}
 	err := client.Run(ctx, &Request{q: "query {}"}, &responseData)
-	is.Equal(err.Error(), "graphql: miscellaneous message as to why the the request was bad")
+	is.True(strings.Contains(err.Error(), "graphql: miscellaneous message as to why the the request was bad"))
 }
 
 func TestDoNoResponse(t *testing.T) {