diff --git a/connection/connection_test.go b/connection/connection_test.go
new file mode 100644
index 0000000..315e068
--- /dev/null
+++ b/connection/connection_test.go
@@ -0,0 +1,42 @@
+package connection
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewConnectionErrorMessages(t *testing.T) {
+	t.Run("Error - Neither WinRM nor SSH", func(t *testing.T) {
+		conf := &Config{}
+
+		_, err := New(conf)
+
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "one of WinRMConfig and SSHConfig must be set")
+	})
+
+	t.Run("Error - Both WinRM and SSH", func(t *testing.T) {
+		winRMConfig := &WinRMConfig{
+			WinRMUsername: "test",
+			WinRMPassword: "test",
+			WinRMHost:     "test",
+		}
+
+		sshConfig := &SSHConfig{
+			SSHUsername: "test",
+			SSHPassword: "test",
+			SSHHost:     "test",
+		}
+
+		conf := &Config{
+			WinRM: winRMConfig,
+			SSH:   sshConfig,
+		}
+
+		_, err := New(conf)
+
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "only one of WinRMConfig and SSHConfig must be set")
+	})
+}