diff --git a/http/errors_test.go b/http/errors_test.go
new file mode 100644
index 0000000..ab31d52
--- /dev/null
+++ b/http/errors_test.go
@@ -0,0 +1,55 @@
+package http
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_IsOTPRequired(t *testing.T) {
+	t.Run("returns OTP required when the ErrOTPRequired variable is passed", func(t *testing.T) {
+		// Given
+		err := ErrOTPRequired
+
+		// When
+		optRequired := IsOTPRequired(err)
+
+		// Then
+		require.True(t, optRequired)
+	})
+	t.Run("returns OTP required when a message 'OTP Required' is returned by API", func(t *testing.T) {
+		// Given
+		err := requestFailedError("OTP Required")
+
+		// When
+		optRequired := IsOTPRequired(err)
+
+		// Then
+		require.True(t, optRequired)
+	})
+	t.Run("returns false when API does not returns 'OPT Required'", func(t *testing.T) {
+		// Given
+		err := requestFailedError("bad request")
+
+		// When
+		optRequired := IsOTPRequired(err)
+
+		// Then
+		require.False(t, optRequired)
+	})
+	t.Run("returns false when an normal error is given", func(t *testing.T) {
+		// Given
+		err := errors.New("bad request")
+
+		// When
+		optRequired := IsOTPRequired(err)
+
+		// Then
+		require.False(t, optRequired)
+	})
+}
+
+func requestFailedError(message string) error {
+	return &RequestFailedError{Message: message}
+}