release: 0.1.0: Phases 0-11: panel, Postfix/DKIM, milter, backup, Docker image

Initial feature-complete implementation of the v1.0 specification (phases 0-11 of `docs/implementation-plan.md`).
Added:
  - Panel (Go, single static binary) with SQLite persistence, one-time
  - Domain management with per-domain DKIM (RSA-2048, generated in pure Go) and
  - Application (sender identity) management: SASL credentials via `sasldb2`,
  - Full Postfix relay config generated from env at container start: SMTPS 465,
  - Journal milter (pure Go, `go-milter`) recording every send to `send_log`;
  … (6 more in CHANGELOG)

Full detail: CHANGELOG.md (0.1.0).

internal/postfix/postfix_test.go

@@ -0,0 +1,118 @@
+package postfix
+
+import (
+	"os"
+	"testing"
+)
+
+func TestRenderSenderLoginMaps(t *testing.T) {
+	// Deliberately unsorted, with two logins sharing one wildcard key
+	// (many-to-one, spec 5.1 §4) to exercise merge + sort.
+	bindings := []Binding{
+		{"@zeta.example", "z1"},
+		{"alerts@alpha.example", "a-listed"},
+		{"@alpha.example", "a2"},
+		{"@alpha.example", "a1"},
+	}
+	got, err := renderSenderLoginMaps(bindings)
+	if err != nil {
+		t.Fatalf("renderSenderLoginMaps: %v", err)
+	}
+	want := "@alpha.example a1,a2\n" +
+		"@zeta.example z1\n" +
+		"alerts@alpha.example a-listed\n"
+	if string(got) != want {
+		t.Errorf("map =\n%q\nwant\n%q", got, want)
+	}
+}
+
+func TestRenderSenderLoginMapsEmpty(t *testing.T) {
+	got, err := renderSenderLoginMaps(nil)
+	if err != nil {
+		t.Fatalf("renderSenderLoginMaps(nil): %v", err)
+	}
+	if len(got) != 0 {
+		t.Errorf("expected empty map, got %q", got)
+	}
+}
+
+func TestRenderSenderLoginMapsDedupesLogin(t *testing.T) {
+	bindings := []Binding{
+		{"@a.example", "dup"},
+		{"@a.example", "dup"},
+	}
+	got, err := renderSenderLoginMaps(bindings)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(got) != "@a.example dup\n" {
+		t.Errorf("map = %q, want single deduped login", got)
+	}
+}
+
+func TestAssertMapSafeRejectsInjection(t *testing.T) {
+	bad := []struct{ addr, login string }{
+		{"@exa mple.com", "log"},
+		{"@example.com\nx y z", "log"},
+		{"@example.com", "log,evil"},
+		{"@example.com", "log in"},
+		{"@example.com", "log@realm"}, // '@' would confuse sasldb realm handling
+		{"", "log"},
+		{"@example.com", ""},
+	}
+	for _, b := range bad {
+		if err := assertMapSafe(b.addr, b.login); err == nil {
+			t.Errorf("assertMapSafe(%q,%q) = nil, want error", b.addr, b.login)
+		}
+	}
+	if err := assertMapSafe("alerts@example.com", "app_1-x"); err != nil {
+		t.Errorf("assertMapSafe of a clean pair errored: %v", err)
+	}
+}
+
+func newTestPostfix(t *testing.T) (*Postfix, *int) {
+	t.Helper()
+	dir := t.TempDir()
+	reloads := 0
+	p := New(dir)
+	p.reload = func() error { reloads++; return nil }
+	return p, &reloads
+}
+
+func TestRebuildSenderLoginMapsWritesAndReloads(t *testing.T) {
+	p, reloads := newTestPostfix(t)
+	if err := p.RebuildSenderLoginMaps([]Binding{{"@example.com", "app1"}}); err != nil {
+		t.Fatalf("RebuildSenderLoginMaps: %v", err)
+	}
+	if *reloads != 1 {
+		t.Errorf("reload called %d times, want 1", *reloads)
+	}
+	data, err := os.ReadFile(p.senderLoginMapsPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(data) != "@example.com app1\n" {
+		t.Errorf("map file = %q", data)
+	}
+}
+
+func TestRebuildRejectsUnsafeWithoutWriting(t *testing.T) {
+	p, reloads := newTestPostfix(t)
+	// Seed a known-good file so we can prove the failed rebuild left it untouched.
+	if err := p.RebuildSenderLoginMaps([]Binding{{"@good.example", "ok"}}); err != nil {
+		t.Fatal(err)
+	}
+	before, _ := os.ReadFile(p.senderLoginMapsPath)
+
+	err := p.RebuildSenderLoginMaps([]Binding{{"@bad.example", "evil\nlogin"}})
+	if err == nil {
+		t.Fatal("expected rebuild to reject unsafe login")
+	}
+	after, _ := os.ReadFile(p.senderLoginMapsPath)
+	if string(after) != string(before) {
+		t.Errorf("map file changed on failed rebuild: %q", after)
+	}
+	if *reloads != 1 {
+		t.Errorf("reload called %d times, want 1 (no reload on failure)", *reloads)
+	}
+}