diff --git a/mockresponder.go b/mockresponder.go
index 5168b78..c39ac74 100644
--- a/mockresponder.go
+++ b/mockresponder.go
@@ -25,6 +25,11 @@ type MockResp struct {
 	served bool
 }
 
+func (mr MockResp) String() string {
+	// return fmt.Sprintf("%s/%d/%v/%s", mr.URL, mr.Code, mr.Err, string(mr.Data))
+	return fmt.Sprintf("%s/%d/%v/%v", mr.URL, mr.Code, mr.Err, mr.served)
+}
+
 // MockRespList is a list of mocked responses, these are the responses that the
 // MockResponder serves, either sequentially or because of a RegEx match.
 type MockRespList []MockResp
@@ -99,9 +104,19 @@ func defaultDoFunc(req *http.Request) (*http.Response, error) {
 		break
 	}
 
-	if !found {
+	// default to 200/OK
+	statusCode := data.Code
+	if statusCode == 0 {
+		statusCode = http.StatusOK
+	}
+
+	if found {
+		// log.Printf("%s <%v>, %d: %v\n", req.Method, req.URL, statusCode, string(data.Data))
+		log.Printf("%s <%v>, %d: %s\n", req.Method, req.URL, statusCode, data)
+	} else {
 		for k, v := range mc.mockData {
-			fmt.Printf("%d: %v/%v/%v/%v\n", k, v.served, v.URL, v.Code, string(v.Data))
+			log.Printf("%d: %v %v %v\n%v\n%v\n", k, v.served, v.URL, v.Code, sanitizeURL(req.URL.String()), string(v.Data))
+			log.Println("**********")
 		}
 		panic("ran out of data")
 	}
@@ -110,12 +125,6 @@ func defaultDoFunc(req *http.Request) (*http.Response, error) {
 		return nil, data.Err
 	}
 
-	// default to 200/OK
-	statusCode := data.Code
-	if statusCode == 0 {
-		statusCode = http.StatusOK
-	}
-
 	resp := &http.Response{
 		StatusCode: statusCode,
 		Body:       io.NopCloser(bytes.NewReader([]byte(data.Data))),
@@ -169,6 +178,7 @@ func (m *MockResponder) LastData() []byte {
 func (m *MockResponder) Empty() bool {
 	for _, d := range m.mockData {
 		if !d.served {
+			log.Println(d)
 			return false
 		}
 	}
diff --git a/mockresponder_test.go b/mockresponder_test.go
index 4df8803..d2d64f4 100644
--- a/mockresponder_test.go
+++ b/mockresponder_test.go
@@ -7,7 +7,9 @@ import (
 	"net/http"
 	"reflect"
 	"runtime"
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -183,3 +185,52 @@ func Test_sanitizeURL(t *testing.T) {
 		})
 	}
 }
+
+func Test_Race(t *testing.T) {
+
+	mrClient, ctx := NewMockResponder()
+	data := MockRespList{
+		MockResp{Code: 200},
+		MockResp{Code: 200},
+	}
+	mrClient.SetData(data)
+
+	done := false
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+
+	mu := sync.Mutex{}
+
+	get := func() {
+		req, _ := http.NewRequestWithContext(ctx, http.MethodGet, "/bla", nil)
+		resp, _ := mrClient.Do(req)
+		defer resp.Body.Close()
+		io.ReadAll(resp.Body)
+	}
+
+	go func() {
+		get()
+		wg.Done()
+	}()
+
+	go func() {
+		get()
+		wg.Done()
+	}()
+
+	go func() {
+		wg.Wait()
+		mu.Lock()
+		done = true
+		mu.Unlock()
+	}()
+
+	doneCheck := func() bool {
+		mu.Lock()
+		defer mu.Unlock()
+		return done
+	}
+
+	assert.Eventually(t, doneCheck, time.Second*5, time.Microsecond*50)
+	assert.True(t, mrClient.Empty())
+}