fix(segment): prevent panic because of non mandatory fields

Fixes #17

segment/basic_account_information.go

@@ -94,12 +94,15 @@ func (a *AccountInformationV5) referencedId() string { return "HKVVB" }
 func (a *AccountInformationV5) sender() string       { return senderBank }
 
 func (a *AccountInformationV5) Account() domain.AccountInformation {
-	accountConnection := a.AccountConnection.Val()
 	info := domain.AccountInformation{
-		AccountConnection: accountConnection,
-		UserID:            a.UserID.Val(),
-		Currency:          a.AccountCurrency.Val(),
-		Name1:             a.Name1.Val(),
+		UserID: a.UserID.Val(),
+		Name1:  a.Name1.Val(),
+	}
+	if a.AccountConnection != nil {
+		info.AccountConnection = a.AccountConnection.Val()
+	}
+	if a.AccountCurrency != nil {
+		info.Currency = a.AccountCurrency.Val()
 	}
 	if a.Name2 != nil {
 		info.Name2 = a.Name2.Val()
@@ -152,12 +155,15 @@ func (a *AccountInformationV6) referencedId() string { return "HKVVB" }
 func (a *AccountInformationV6) sender() string       { return senderBank }
 
 func (a *AccountInformationV6) Account() domain.AccountInformation {
-	accountConnection := a.AccountConnection.Val()
 	info := domain.AccountInformation{
-		AccountConnection: accountConnection,
-		UserID:            a.UserID.Val(),
-		Currency:          a.AccountCurrency.Val(),
-		Name1:             a.Name1.Val(),
+		UserID: a.UserID.Val(),
+		Name1:  a.Name1.Val(),
+	}
+	if a.AccountConnection != nil {
+		info.AccountConnection = a.AccountConnection.Val()
+	}
+	if a.AccountCurrency != nil {
+		info.Currency = a.AccountCurrency.Val()
 	}
 	if a.Name2 != nil {
 		info.Name2 = a.Name2.Val()

segment/basic_account_information_test.go

@@ -0,0 +1,75 @@
+package segment
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/mitch000001/go-hbci/domain"
+	"github.com/mitch000001/go-hbci/element"
+)
+
+func TestAccountInformationSegment_Account(t *testing.T) {
+	testCases := []struct {
+		desc            string
+		segment         AccountInformation
+		expectedAccount domain.AccountInformation
+	}{
+		{
+			desc: "v4 all mandatory fields set",
+			segment: &AccountInformationV4{
+				AccountConnection: element.NewAccountConnection(
+					domain.AccountConnection{
+						AccountID:   "123456789",
+						CountryCode: 280,
+						BankID:      "1000000",
+					},
+				),
+				UserID:          element.NewIdentification("user"),
+				AccountCurrency: element.NewCurrency("EUR"),
+				Name1:           element.NewAlphaNumeric("name", 27),
+			},
+			expectedAccount: domain.AccountInformation{
+				AccountConnection: domain.AccountConnection{
+					AccountID:   "123456789",
+					CountryCode: 280,
+					BankID:      "1000000",
+				},
+				UserID:   "user",
+				Currency: "EUR",
+				Name1:    "name",
+			},
+		},
+		{
+			desc: "v5 all mandatory fields set",
+			segment: &AccountInformationV5{
+				UserID: element.NewIdentification("user"),
+				Name1:  element.NewAlphaNumeric("name", 27),
+			},
+			expectedAccount: domain.AccountInformation{
+				UserID: "user",
+				Name1:  "name",
+			},
+		},
+		{
+			desc: "v6 all mandatory fields set",
+			segment: &AccountInformationV6{
+				UserID: element.NewIdentification("user"),
+				Name1:  element.NewAlphaNumeric("name", 27),
+			},
+			expectedAccount: domain.AccountInformation{
+				UserID: "user",
+				Name1:  "name",
+			},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			account := tt.segment.Account()
+
+			if !reflect.DeepEqual(tt.expectedAccount, account) {
+				t.Errorf("Expected accout to equal\n%v\n\tgot\n%v\n", tt.expectedAccount, account)
+			}
+		})
+	}
+}