diff --git a/client_test.go b/client_test.go
index 38b9411..9665679 100644
--- a/client_test.go
+++ b/client_test.go
@@ -28,6 +28,7 @@ func (t *closureTransport) RoundTrip(req *http.Request) (*http.Response, error)
 func TestUserAgentHeader(t *testing.T) {
 	var userAgent string
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -57,6 +58,7 @@ func TestUserAgentHeader(t *testing.T) {
 func TestRetryAfter(t *testing.T) {
 	retryCountHeaders := make([]string, 0)
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -99,6 +101,7 @@ func TestRetryAfter(t *testing.T) {
 func TestDeleteRetryCountHeader(t *testing.T) {
 	retryCountHeaders := make([]string, 0)
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -137,6 +140,7 @@ func TestDeleteRetryCountHeader(t *testing.T) {
 func TestOverwriteRetryCountHeader(t *testing.T) {
 	retryCountHeaders := make([]string, 0)
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -175,6 +179,7 @@ func TestOverwriteRetryCountHeader(t *testing.T) {
 func TestRetryAfterMs(t *testing.T) {
 	attempts := 0
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -209,6 +214,7 @@ func TestRetryAfterMs(t *testing.T) {
 
 func TestContextCancel(t *testing.T) {
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -237,6 +243,7 @@ func TestContextCancel(t *testing.T) {
 
 func TestContextCancelDelay(t *testing.T) {
 	client := openai.NewClient(
+		option.WithAPIKey("My API Key"),
 		option.WithHTTPClient(&http.Client{
 			Transport: &closureTransport{
 				fn: func(req *http.Request) (*http.Response, error) {
@@ -273,6 +280,7 @@ func TestContextDeadline(t *testing.T) {
 
 	go func() {
 		client := openai.NewClient(
+			option.WithAPIKey("My API Key"),
 			option.WithHTTPClient(&http.Client{
 				Transport: &closureTransport{
 					fn: func(req *http.Request) (*http.Response, error) {
@@ -318,6 +326,7 @@ func TestContextDeadlineStreaming(t *testing.T) {
 
 	go func() {
 		client := openai.NewClient(
+			option.WithAPIKey("My API Key"),
 			option.WithHTTPClient(&http.Client{
 				Transport: &closureTransport{
 					fn: func(req *http.Request) (*http.Response, error) {
@@ -371,6 +380,7 @@ func TestContextDeadlineStreamingWithRequestTimeout(t *testing.T) {
 
 	go func() {
 		client := openai.NewClient(
+			option.WithAPIKey("My API Key"),
 			option.WithHTTPClient(&http.Client{
 				Transport: &closureTransport{
 					fn: func(req *http.Request) (*http.Response, error) {