Add UI master key setup and change flows

session/session_test.go

@@ -391,6 +391,68 @@ func TestSaveUsesRemoteTargetWhenVaultWasOpenedFromWebDAV(t *testing.T) {
 	}
 }
 
+func TestChangeMasterKeyReencryptsSavedAndLockedVault(t *testing.T) {
+	t.Parallel()
+
+	originalKey := vault.MasterKey{Password: "old-password"}
+	updatedKey := vault.MasterKey{
+		Password:    "new-password",
+		KeyFileData: []byte("updated-key-file"),
+	}
+	model := vault.Model{
+		Entries: []vault.Entry{
+			{
+				ID:       "entry-1",
+				Title:    "Vault Console",
+				Username: "dannyocean",
+				Password: "token-1",
+				URL:      "https://vault.crew.example.invalid",
+				Path:     []string{"Root", "Internet"},
+			},
+		},
+	}
+
+	path := filepath.Join(t.TempDir(), "keepassgo.kdbx")
+
+	var sess Manager
+	if err := sess.Create(model, originalKey); err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+	if err := sess.SaveAs(path); err != nil {
+		t.Fatalf("SaveAs() error = %v", err)
+	}
+	if err := sess.Lock(); err != nil {
+		t.Fatalf("Lock() error = %v", err)
+	}
+	if err := sess.ChangeMasterKey(updatedKey); err != nil {
+		t.Fatalf("ChangeMasterKey() error = %v", err)
+	}
+	if err := sess.Save(); err != nil {
+		t.Fatalf("Save() error = %v", err)
+	}
+
+	if err := sess.Unlock(updatedKey); err != nil {
+		t.Fatalf("Unlock(updatedKey) error = %v", err)
+	}
+
+	current, err := sess.Current()
+	if err != nil {
+		t.Fatalf("Current() error = %v", err)
+	}
+	got := current.EntriesInPath([]string{"Root", "Internet"})
+	if len(got) != 1 || got[0].Title != "Vault Console" {
+		t.Fatalf("Current() entries = %#v, want Vault Console entry after ChangeMasterKey", got)
+	}
+
+	var reopened Manager
+	if err := reopened.Open(path, updatedKey); err != nil {
+		t.Fatalf("Open(updatedKey) error = %v", err)
+	}
+	if err := reopened.Open(path, originalKey); !errors.Is(err, vault.ErrInvalidMasterKey) {
+		t.Fatalf("Open(originalKey) error = %v, want ErrInvalidMasterKey", err)
+	}
+}
+
 func TestSavePreservesOpenedKDBXSecuritySettings(t *testing.T) {
 	t.Parallel()