src/main/java/net/hostsharing/hsadminng/hs/office/coopassets/HsOfficeCoopAssetsTransactionEntity.java

@@ -29,7 +29,7 @@ import static net.hostsharing.hsadminng.stringify.Stringify.stringify;
 public class HsOfficeCoopAssetsTransactionEntity implements Stringifyable, HasUuid {
 
     private static Stringify<HsOfficeCoopAssetsTransactionEntity> stringify = stringify(HsOfficeCoopAssetsTransactionEntity.class)
-            .withProp(e -> ofNullable(e.getMembership()).map(HsOfficeMembershipEntity::getMemberNumber).orElse(null))
+            .withProp(HsOfficeCoopAssetsTransactionEntity::getMemberNumber)
             .withProp(HsOfficeCoopAssetsTransactionEntity::getValueDate)
             .withProp(HsOfficeCoopAssetsTransactionEntity::getTransactionType)
             .withProp(HsOfficeCoopAssetsTransactionEntity::getAssetValue)
@@ -63,6 +63,11 @@ public class HsOfficeCoopAssetsTransactionEntity implements Stringifyable, HasUu
     @Column(name = "comment")
     private String comment;
 
+
+    public Integer getMemberNumber() {
+        return ofNullable(membership).map(HsOfficeMembershipEntity::getMemberNumber).orElse(null);
+    }
+
     @Override
     public String toString() {
         return stringify.apply(this);
@@ -70,6 +75,6 @@ public class HsOfficeCoopAssetsTransactionEntity implements Stringifyable, HasUu
 
     @Override
     public String toShortString() {
-        return membership.getMemberNumber() + new DecimalFormat("+0.00").format(assetValue);
+        return "%s%+1.2f".formatted(getMemberNumber(), assetValue);
     }
 }

src/main/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionEntity.java

@@ -11,6 +11,7 @@ import jakarta.persistence.*;
 import java.time.LocalDate;
 import java.util.UUID;
 
+import static java.util.Optional.ofNullable;
 import static net.hostsharing.hsadminng.stringify.Stringify.stringify;
 
 @Entity
@@ -24,7 +25,7 @@ import static net.hostsharing.hsadminng.stringify.Stringify.stringify;
 public class HsOfficeCoopSharesTransactionEntity implements Stringifyable, HasUuid {
 
     private static Stringify<HsOfficeCoopSharesTransactionEntity> stringify = stringify(HsOfficeCoopSharesTransactionEntity.class)
-            .withProp(e -> e.getMembership().getMemberNumber())
+            .withProp(HsOfficeCoopSharesTransactionEntity::getMemberNumber)
             .withProp(HsOfficeCoopSharesTransactionEntity::getValueDate)
             .withProp(HsOfficeCoopSharesTransactionEntity::getTransactionType)
             .withProp(HsOfficeCoopSharesTransactionEntity::getShareCount)
@@ -62,8 +63,12 @@ public class HsOfficeCoopSharesTransactionEntity implements Stringifyable, HasUu
         return stringify.apply(this);
     }
 
+    public Integer getMemberNumber() {
+        return ofNullable(membership).map(HsOfficeMembershipEntity::getMemberNumber).orElse(null);
+    }
+
     @Override
     public String toShortString() {
-        return "%s%+d".formatted(membership.getMemberNumber(), shareCount);
+        return "%s%+d".formatted(getMemberNumber(), shareCount);
     }
 }

src/test/java/net/hostsharing/hsadminng/hs/office/coopassets/HsOfficeCoopAssetsTransactionEntityUnitTest.java

@@ -17,6 +17,7 @@ class HsOfficeCoopAssetsTransactionEntityUnitTest {
             .transactionType(HsOfficeCoopAssetsTransactionType.DEPOSIT)
             .assetValue(new BigDecimal("128.00"))
             .build();
+    final HsOfficeCoopAssetsTransactionEntity givenEmptyCoopAssetsTransaction = HsOfficeCoopAssetsTransactionEntity.builder().build();
 
     @Test
     void toStringContainsAlmostAllPropertiesAccount() {
@@ -31,4 +32,18 @@ class HsOfficeCoopAssetsTransactionEntityUnitTest {
 
         assertThat(result).isEqualTo("300001+128.00");
     }
+
+    @Test
+    void toStringWithEmptyTransactionDoesNotThrowException() {
+        final var result = givenEmptyCoopAssetsTransaction.toString();
+
+        assertThat(result).isEqualTo("CoopAssetsTransaction()");
+    }
+
+    @Test
+    void toShortStringEmptyTransactionDoesNotThrowException() {
+        final var result = givenEmptyCoopAssetsTransaction.toShortString();
+
+        assertThat(result).isEqualTo("nullnu");
+    }
 }

src/test/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionEntityUnitTest.java

@@ -16,6 +16,7 @@ class HsOfficeCoopSharesTransactionEntityUnitTest {
             .transactionType(HsOfficeCoopSharesTransactionType.SUBSCRIPTION)
             .shareCount(4)
             .build();
+    final HsOfficeCoopSharesTransactionEntity givenEmptyCoopSharesTransaction = HsOfficeCoopSharesTransactionEntity.builder().build();
 
     @Test
     void toStringContainsAlmostAllPropertiesAccount() {
@@ -25,9 +26,23 @@ class HsOfficeCoopSharesTransactionEntityUnitTest {
     }
 
     @Test
-    void toShortStringContainsOnlyMemberNumberAndshareCountOnly() {
+    void toShortStringContainsOnlyMemberNumberAndShareCountOnly() {
         final var result = givenCoopSharesTransaction.toShortString();
 
         assertThat(result).isEqualTo("300001+4");
     }
+
+    @Test
+    void toStringEmptyTransactionDoesNotThrowException() {
+        final var result = givenEmptyCoopSharesTransaction.toString();
+
+        assertThat(result).isEqualTo("CoopShareTransaction(0)");
+    }
+
+    @Test
+    void toShortStringEmptyTransactionDoesNotThrowException() {
+        final var result = givenEmptyCoopSharesTransaction.toShortString();
+
+        assertThat(result).isEqualTo("null+0");
+    }
 }