diff --git a/test/mini-oidc/storage/storage.go b/test/mini-oidc/storage/storage.go
index de1f79f49b..ef05af87f0 100644
--- a/test/mini-oidc/storage/storage.go
+++ b/test/mini-oidc/storage/storage.go
@@ -5,7 +5,6 @@ import (
 	"crypto/rand"
 	"crypto/rsa"
 	"errors"
-	"fmt"
 	"math/big"
 	"strings"
 	"sync"
@@ -131,7 +130,7 @@ func (s *Storage) CheckUsernamePassword(username, password, id string) error {
 	defer s.lock.Unlock()
 	request, ok := s.authRequests[id]
 	if !ok {
-		return fmt.Errorf("request not found")
+		return errors.New("request not found")
 	}
 
 	// for demonstration purposes we'll check we'll have a simple user store and
@@ -149,7 +148,7 @@ func (s *Storage) CheckUsernamePassword(username, password, id string) error {
 		request.done = true
 		return nil
 	}
-	return fmt.Errorf("username or password wrong")
+	return errors.New("username or password wrong")
 }
 
 func (s *Storage) CheckUsernamePasswordSimple(username, password string) error {
@@ -160,7 +159,7 @@ func (s *Storage) CheckUsernamePasswordSimple(username, password string) error {
 	if user != nil && user.Password == password {
 		return nil
 	}
-	return fmt.Errorf("username or password wrong")
+	return errors.New("username or password wrong")
 }
 
 // CreateAuthRequest implements the op.Storage interface
@@ -195,7 +194,7 @@ func (s *Storage) AuthRequestByID(ctx context.Context, id string) (op.AuthReques
 	defer s.lock.Unlock()
 	request, ok := s.authRequests[id]
 	if !ok {
-		return nil, fmt.Errorf("request not found")
+		return nil, errors.New("request not found")
 	}
 	return request, nil
 }
@@ -211,7 +210,7 @@ func (s *Storage) AuthRequestByCode(ctx context.Context, code string) (op.AuthRe
 		return requestID, ok
 	}()
 	if !ok {
-		return nil, fmt.Errorf("code invalid or expired")
+		return nil, errors.New("code invalid or expired")
 	}
 	return s.AuthRequestByID(ctx, requestID)
 }
@@ -327,7 +326,7 @@ func (s *Storage) TokenRequestByRefreshToken(ctx context.Context, refreshToken s
 	defer s.lock.Unlock()
 	token, ok := s.refreshTokens[refreshToken]
 	if !ok {
-		return nil, fmt.Errorf("invalid refresh_token")
+		return nil, errors.New("invalid refresh_token")
 	}
 	return RefreshTokenRequestFromBusiness(token), nil
 }
@@ -424,7 +423,7 @@ func (s *Storage) GetClientByClientID(ctx context.Context, clientID string) (op.
 	defer s.lock.Unlock()
 	client, ok := s.clients[clientID]
 	if !ok {
-		return nil, fmt.Errorf("client not found")
+		return nil, errors.New("client not found")
 	}
 	return RedirectGlobsClient(client), nil
 }
@@ -436,12 +435,12 @@ func (s *Storage) AuthorizeClientIDSecret(ctx context.Context, clientID, clientS
 	defer s.lock.Unlock()
 	client, ok := s.clients[clientID]
 	if !ok {
-		return fmt.Errorf("client not found")
+		return errors.New("client not found")
 	}
 	// for this example we directly check the secret
 	// obviously you would not have the secret in plain text, but rather hashed and salted (e.g. using bcrypt)
 	if client.secret != clientSecret {
-		return fmt.Errorf("invalid secret")
+		return errors.New("invalid secret")
 	}
 	return nil
 }
@@ -469,7 +468,7 @@ func (s *Storage) SetUserinfoFromToken(ctx context.Context, userinfo *oidc.UserI
 		return token, ok
 	}()
 	if !ok {
-		return fmt.Errorf("token is invalid or has expired")
+		return errors.New("token is invalid or has expired")
 	}
 	// the userinfo endpoint should support CORS. If it's not possible to specify a specific origin in the CORS handler,
 	// and you have to specify a wildcard (*) origin, then you could also check here if the origin which called the userinfo endpoint here directly
@@ -478,7 +477,7 @@ func (s *Storage) SetUserinfoFromToken(ctx context.Context, userinfo *oidc.UserI
 	// if origin != "" {
 	//	client, ok := s.clients[token.ApplicationID]
 	//	if !ok {
-	//		return fmt.Errorf("client not found")
+	//		return errors.New("client not found")
 	//	}
 	//	if err := checkAllowedOrigins(client.allowedOrigins, origin); err != nil {
 	//		return err
@@ -497,7 +496,7 @@ func (s *Storage) SetIntrospectionFromToken(ctx context.Context, introspection *
 		return token, ok
 	}()
 	if !ok {
-		return fmt.Errorf("token is invalid or has expired")
+		return errors.New("token is invalid or has expired")
 	}
 	// check if the client is part of the requested audience
 	for _, aud := range token.Audience {
@@ -520,7 +519,7 @@ func (s *Storage) SetIntrospectionFromToken(ctx context.Context, introspection *
 			return nil
 		}
 	}
-	return fmt.Errorf("token is not valid for this client")
+	return errors.New("token is not valid for this client")
 }
 
 // GetPrivateClaimsFromScopes implements the op.Storage interface
@@ -546,11 +545,11 @@ func (s *Storage) GetKeyByIDAndClientID(ctx context.Context, keyID, clientID str
 	defer s.lock.Unlock()
 	service, ok := s.services[clientID]
 	if !ok {
-		return nil, fmt.Errorf("clientID not found")
+		return nil, errors.New("clientID not found")
 	}
 	key, ok := service.keys[keyID]
 	if !ok {
-		return nil, fmt.Errorf("key not found")
+		return nil, errors.New("key not found")
 	}
 	return &jose.JSONWebKey{
 		KeyID: keyID,
@@ -601,7 +600,7 @@ func (s *Storage) renewRefreshToken(currentRefreshToken string) (string, string,
 	defer s.lock.Unlock()
 	refreshToken, ok := s.refreshTokens[currentRefreshToken]
 	if !ok {
-		return "", "", fmt.Errorf("invalid refresh token")
+		return "", "", errors.New("invalid refresh token")
 	}
 	// deletes the refresh token and all access tokens which were issued based on this refresh token
 	delete(s.refreshTokens, currentRefreshToken)
@@ -642,7 +641,7 @@ func (s *Storage) setUserinfo(ctx context.Context, userInfo *oidc.UserInfo, user
 	defer s.lock.Unlock()
 	user := s.userStore.GetUserByID(userID)
 	if user == nil {
-		return fmt.Errorf("user not found")
+		return errors.New("user not found")
 	}
 	for _, scope := range scopes {
 		switch scope {
diff --git a/test/tls2jwt/tls2jwt.go b/test/tls2jwt/tls2jwt.go
index 994a16a0b7..b73f668b3b 100644
--- a/test/tls2jwt/tls2jwt.go
+++ b/test/tls2jwt/tls2jwt.go
@@ -61,6 +61,6 @@ func main() {
 		os.Exit(0)
 	}
 
-	fmt.Fprintf(os.Stderr, "Error: Couldn't sign the token (unsupported algorithm?)\n")
+	fmt.Fprint(os.Stderr, "Error: Couldn't sign the token (unsupported algorithm?)\n")
 	os.Exit(1)
 }