Add comprehensive tests for SMTP client functionality

Introduce new tests to verify behaviors of client methods including SetLogAuthData, SetDSNRcptNotifyOption, SetDSNMailReturnOption, HasConnection, and UpdateDeadline. Ensure these tests cover various scenarios such as successful operations, edge cases, and failure conditions.

smtp/smtp_test.go

@@ -3193,6 +3193,209 @@ func TestClient_SetLogger(t *testing.T) {
 	})
 }
 
+func TestClient_SetLogAuthData(t *testing.T) {
+	t.Run("set log auth data to true", func(t *testing.T) {
+		client := &Client{}
+		client.SetLogAuthData()
+		if !client.logAuthData {
+			t.Fatalf("expected log auth data to be true")
+		}
+	})
+}
+
+func TestClient_SetDSNRcptNotifyOption(t *testing.T) {
+	tests := []string{"NEVER", "SUCCESS", "FAILURE", "DELAY"}
+	for _, test := range tests {
+		t.Run("set dsn rcpt notify option to "+test, func(t *testing.T) {
+			client := &Client{}
+			client.SetDSNRcptNotifyOption(test)
+			if !strings.EqualFold(client.dsnrntype, test) {
+				t.Errorf("expected dsn rcpt notify option to be %s, got %s", test, client.dsnrntype)
+			}
+		})
+	}
+}
+
+func TestClient_SetDSNMailReturnOption(t *testing.T) {
+	tests := []string{"HDRS", "FULL"}
+	for _, test := range tests {
+		t.Run("set dsn mail return option to "+test, func(t *testing.T) {
+			client := &Client{}
+			client.SetDSNMailReturnOption(test)
+			if !strings.EqualFold(client.dsnmrtype, test) {
+				t.Errorf("expected dsn mail return option to be %s, got %s", test, client.dsnmrtype)
+			}
+		})
+	}
+}
+
+func TestClient_HasConnection(t *testing.T) {
+	t.Run("client has connection", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		PortAdder.Add(1)
+		serverPort := int(TestServerPortBase + PortAdder.Load())
+		featureSet := "250-DSN\r\n250 STARTTLS"
+		go func() {
+			if err := simpleSMTPServer(ctx, t, &serverProps{
+				FeatureSet: featureSet,
+				ListenPort: serverPort,
+			},
+			); err != nil {
+				t.Errorf("failed to start test server: %s", err)
+				return
+			}
+		}()
+		time.Sleep(time.Millisecond * 30)
+		client, err := Dial(fmt.Sprintf("%s:%d", TestServerAddr, serverPort))
+		if err != nil {
+			t.Fatalf("failed to dial to test server: %s", err)
+		}
+		t.Cleanup(func() {
+			if err = client.Close(); err != nil {
+				t.Errorf("failed to close client: %s", err)
+			}
+		})
+		if !client.HasConnection() {
+			t.Error("expected client to have a connection")
+		}
+	})
+	t.Run("client has no connection", func(t *testing.T) {
+		client := &Client{}
+		if client.HasConnection() {
+			t.Error("expected client to have no connection")
+		}
+	})
+	t.Run("client has no connection after close", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		PortAdder.Add(1)
+		serverPort := int(TestServerPortBase + PortAdder.Load())
+		featureSet := "250-DSN\r\n250 STARTTLS"
+		go func() {
+			if err := simpleSMTPServer(ctx, t, &serverProps{
+				FeatureSet: featureSet,
+				ListenPort: serverPort,
+			},
+			); err != nil {
+				t.Errorf("failed to start test server: %s", err)
+				return
+			}
+		}()
+		time.Sleep(time.Millisecond * 30)
+		client, err := Dial(fmt.Sprintf("%s:%d", TestServerAddr, serverPort))
+		if err != nil {
+			t.Fatalf("failed to dial to test server: %s", err)
+		}
+		if err = client.Close(); err != nil {
+			t.Errorf("failed to close client: %s", err)
+		}
+		if client.HasConnection() {
+			t.Error("expected client to have no connection after close")
+		}
+	})
+	t.Run("client has no connection after quit", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		PortAdder.Add(1)
+		serverPort := int(TestServerPortBase + PortAdder.Load())
+		featureSet := "250-DSN\r\n250 STARTTLS"
+		go func() {
+			if err := simpleSMTPServer(ctx, t, &serverProps{
+				FeatureSet: featureSet,
+				ListenPort: serverPort,
+			},
+			); err != nil {
+				t.Errorf("failed to start test server: %s", err)
+				return
+			}
+		}()
+		time.Sleep(time.Millisecond * 30)
+		client, err := Dial(fmt.Sprintf("%s:%d", TestServerAddr, serverPort))
+		if err != nil {
+			t.Fatalf("failed to dial to test server: %s", err)
+		}
+		if err = client.Quit(); err != nil {
+			t.Errorf("failed to quit client: %s", err)
+		}
+		if client.HasConnection() {
+			t.Error("expected client to have no connection after quit")
+		}
+	})
+}
+
+func TestClient_UpdateDeadline(t *testing.T) {
+	t.Run("update deadline on sane client succeeds", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		PortAdder.Add(1)
+		serverPort := int(TestServerPortBase + PortAdder.Load())
+		featureSet := "250-DSN\r\n250 STARTTLS"
+		go func() {
+			if err := simpleSMTPServer(ctx, t, &serverProps{
+				FeatureSet: featureSet,
+				ListenPort: serverPort,
+			},
+			); err != nil {
+				t.Errorf("failed to start test server: %s", err)
+				return
+			}
+		}()
+		time.Sleep(time.Millisecond * 30)
+		client, err := Dial(fmt.Sprintf("%s:%d", TestServerAddr, serverPort))
+		if err != nil {
+			t.Fatalf("failed to dial to test server: %s", err)
+		}
+		t.Cleanup(func() {
+			if err = client.Close(); err != nil {
+				t.Errorf("failed to close client: %s", err)
+			}
+		})
+		if err = client.UpdateDeadline(time.Millisecond * 500); err != nil {
+			t.Errorf("failed to update connection deadline: %s", err)
+		}
+	})
+	t.Run("update deadline on no connection should fail", func(t *testing.T) {
+		client := &Client{}
+		var err error
+		if err = client.UpdateDeadline(time.Millisecond * 500); err == nil {
+			t.Error("expected client deadline update to fail on no connection")
+		}
+		expError := "smtp: client has no connection"
+		if !strings.EqualFold(err.Error(), expError) {
+			t.Errorf("expected error to be %q, got: %q", expError, err)
+		}
+	})
+	t.Run("update deadline on closed client should fail", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		PortAdder.Add(1)
+		serverPort := int(TestServerPortBase + PortAdder.Load())
+		featureSet := "250-DSN\r\n250 STARTTLS"
+		go func() {
+			if err := simpleSMTPServer(ctx, t, &serverProps{
+				FeatureSet: featureSet,
+				ListenPort: serverPort,
+			},
+			); err != nil {
+				t.Errorf("failed to start test server: %s", err)
+				return
+			}
+		}()
+		time.Sleep(time.Millisecond * 30)
+		client, err := Dial(fmt.Sprintf("%s:%d", TestServerAddr, serverPort))
+		if err != nil {
+			t.Fatalf("failed to dial to test server: %s", err)
+		}
+		if err = client.Close(); err != nil {
+			t.Errorf("failed to close client: %s", err)
+		}
+		if err = client.UpdateDeadline(time.Millisecond * 500); err == nil {
+			t.Error("expected client deadline update to fail on closed client")
+		}
+	})
+}
+
 // faker is a struct embedding io.ReadWriter to simulate network connections for testing purposes.
 type faker struct {
 	io.ReadWriter