From c58aa354548ced165f2201261b5fe1ceea00e8c2 Mon Sep 17 00:00:00 2001
From: Winni Neessen <wn@neessen.net>
Date: Mon, 11 Nov 2024 18:25:39 +0100
Subject: [PATCH] Add tests for Client debug logging behavior

Introduce unit tests to verify the behavior of the debug logging in the Client. Confirm that logs are correctly produced when debug mode is enabled and appropriately suppressed when it is disabled.
---
 smtp/smtp_test.go | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/smtp/smtp_test.go b/smtp/smtp_test.go
index 3fb84de..03777d5 100644
--- a/smtp/smtp_test.go
+++ b/smtp/smtp_test.go
@@ -3512,6 +3512,34 @@ func TestClient_GetTLSConnectionState(t *testing.T) {
 	})
 }
 
+func TestClient_debugLog(t *testing.T) {
+	t.Run("debug log is enabled", func(t *testing.T) {
+		buffer := bytes.NewBuffer(nil)
+		logger := log.New(buffer, log.LevelDebug)
+		client := &Client{logger: logger, debug: true}
+		client.debugLog(log.DirClientToServer, "%s", "simple string")
+		client.debugLog(log.DirServerToClient, "%d", 1234)
+		want := "DEBUG: C --> S: simple string"
+		if !strings.Contains(buffer.String(), want) {
+			t.Errorf("expected debug log to contain %q, got: %q", want, buffer.String())
+		}
+		want = "DEBUG: C <-- S: 1234"
+		if !strings.Contains(buffer.String(), want) {
+			t.Errorf("expected debug log to contain %q, got: %q", want, buffer.String())
+		}
+	})
+	t.Run("debug log is disable", func(t *testing.T) {
+		buffer := bytes.NewBuffer(nil)
+		logger := log.New(buffer, log.LevelDebug)
+		client := &Client{logger: logger, debug: false}
+		client.debugLog(log.DirClientToServer, "%s", "simple string")
+		client.debugLog(log.DirServerToClient, "%d", 1234)
+		if buffer.Len() > 0 {
+			t.Errorf("expected debug log to be empty, got: %q", buffer.String())
+		}
+	})
+}
+
 // faker is a struct embedding io.ReadWriter to simulate network connections for testing purposes.
 type faker struct {
 	io.ReadWriter