Show this Postfix's retry policy on Mail queue and delivery history.

Numbers come from a one-shot postconf -h at panel start so a manual override is visible after restart, without inventing an attempt count.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/postfix/duration_test.go

@@ -0,0 +1,64 @@
+package postfix
+
+import (
+	"testing"
+	"time"
+)
+
+func TestParseDuration(t *testing.T) {
+	cases := []struct {
+		in   string
+		want time.Duration
+	}{
+		{"5d", 5 * 24 * time.Hour},
+		{"300s", 300 * time.Second},
+		{"4000s", 4000 * time.Second},
+		{"1h", time.Hour},
+		{"0", 0},
+		{"0s", 0},
+		{"300", 300 * time.Second},
+		{" 300s ", 300 * time.Second},
+		{"1h7m", time.Hour + 7*time.Minute},
+		{"1w", 7 * 24 * time.Hour},
+		{"2m", 2 * time.Minute},
+	}
+	for _, tc := range cases {
+		got, err := ParseDuration(tc.in)
+		if err != nil {
+			t.Errorf("ParseDuration(%q): %v", tc.in, err)
+			continue
+		}
+		if got != tc.want {
+			t.Errorf("ParseDuration(%q) = %v, want %v", tc.in, got, tc.want)
+		}
+	}
+}
+
+func TestParseDurationRejectsInvalid(t *testing.T) {
+	for _, in := range []string{"", "foo", "5x", "-300s", "s", "1h 5x"} {
+		if _, err := ParseDuration(in); err == nil {
+			t.Errorf("ParseDuration(%q) = nil, want error", in)
+		}
+	}
+}
+
+func TestFormatDuration(t *testing.T) {
+	cases := []struct {
+		in   time.Duration
+		want string
+	}{
+		{5 * 24 * time.Hour, "5 days"},
+		{300 * time.Second, "5 minutes"},
+		{4000 * time.Second, "about 1 hour 7 minutes"},
+		{time.Hour, "1 hour"},
+		{0, "0 seconds"},
+		{time.Second, "1 second"},
+		{2 * time.Minute, "2 minutes"},
+		{24 * time.Hour, "1 day"},
+	}
+	for _, tc := range cases {
+		if got := FormatDuration(tc.in); got != tc.want {
+			t.Errorf("FormatDuration(%v) = %q, want %q", tc.in, got, tc.want)
+		}
+	}
+}