make IBAN random generation independent per generation

- create new instances of Randoms where necessary, so that adding/removing IBAN entries won't affect any IBANs that are subsequently generated. - update tests to use assertAll, so it's easier to check & update each value
arturmkrtchyan · Jan 8, 2024 · 91866cb · 91866cb
1 parent cf63318
commit 91866cb
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Showing 4 changed files with 42 additions and 21 deletions.
diff --git a/src/main/java/org/iban4j/Iban.java b/src/main/java/org/iban4j/Iban.java
@@ -413,11 +413,17 @@ public Iban build(boolean validate) throws IbanFormatException,
          */
         public Iban buildRandom() throws IbanFormatException,
                 IllegalArgumentException, UnsupportedCountryException {
+
+            // Create a new seeded Random, so it doesn't matter how this Random is used, it won't affect subsequent usages
+            // of the original Random. (which can impact seeded behaviour when many IBANs are generated or the number of
+            // IBAN entries change).
+            final Random random = new Random(this.random.nextInt());
+
             if (countryCode == null) {
                 List<CountryCode> countryCodes = BbanStructure.supportedCountries();
                 this.countryCode(countryCodes.get(random.nextInt(countryCodes.size())));
             }
-            fillMissingFieldsRandomly();
+            fillMissingFieldsRandomly(random);
             return build();
         }
 
@@ -511,7 +517,7 @@ private void require(final CountryCode countryCode,
             }
         }
 
-        private void fillMissingFieldsRandomly() {
+        private void fillMissingFieldsRandomly(final Random random) {
             final BbanStructure structure = BbanStructure.forCountry(countryCode);
 
             if (structure == null) {

diff --git a/src/main/java/org/iban4j/bban/BbanStructureEntry.java b/src/main/java/org/iban4j/bban/BbanStructureEntry.java
@@ -122,6 +122,12 @@ public String getRandom() {
     }
 
     public String getRandom(Random random) {
+
+        // Create a new seeded Random, so it doesn't matter how this Random is used, it won't affect subsequent usages
+        // of the original Random. (which can impact seeded behaviour when many IBANs are generated or the number of
+        // IBAN entries change).
+        random = new Random(random.nextInt());
+
         StringBuilder s = new StringBuilder();
         char[] charChoices = charByCharacterType.get(characterType);
         if (charChoices == null) {

diff --git a/src/test/java/org/iban4j/IbanTest.java b/src/test/java/org/iban4j/IbanTest.java
@@ -287,11 +287,12 @@ public void ibanConstructionRandom() {
         }
 
         @Test
-        @Disabled
         public void ibanConstructionSeeded() {
-            assertIbanUtilRandomWithSeedEquals("FR87 8734 4468 89P1 RIYK UO5K 809", 1);
-            assertIbanUtilRandomWithSeedEquals("FI79 2079 0697 8464 44", 2);
-            assertIbanUtilRandomWithSeedEquals("FO71 0018 2949 1527 41", 3);
+            assertAll(
+                () -> assertIbanUtilRandomWithSeedEquals("GL41 1918 0836 9682 13", 1),
+                () -> assertIbanUtilRandomWithSeedEquals("FR17 0679 7098 8804 5NYW S75F D50", 2),
+                () -> assertIbanUtilRandomWithSeedEquals("EG45 0882 2804 0304 6660 9507 6091 3", 3)
+            );
         }
 
         private static void assertIbanUtilRandomWithSeedEquals(
@@ -307,11 +308,12 @@ private static void assertIbanUtilRandomWithSeedEquals(
         }
 
         @Test
-        @Disabled
         public void ibanBuilderConstructionSeeded() {
-            assertIbanBuilderRandomWithSeedEquals("FR87 8734 4468 89P1 RIYK UO5K 809", 1);
-            assertIbanBuilderRandomWithSeedEquals("FI79 2079 0697 8464 44", 2);
-            assertIbanBuilderRandomWithSeedEquals("FO71 0018 2949 1527 41", 3);
+            assertAll(
+                () -> assertIbanBuilderRandomWithSeedEquals("GL41 1918 0836 9682 13", 1),
+                () -> assertIbanBuilderRandomWithSeedEquals("FR17 0679 7098 8804 5NYW S75F D50", 2),
+                () -> assertIbanBuilderRandomWithSeedEquals("EG45 0882 2804 0304 6660 9507 6091 3", 3)
+            );
         }
 
         private static void assertIbanBuilderRandomWithSeedEquals(

diff --git a/src/test/java/org/iban4j/bban/BbanStructureEntryTest.java b/src/test/java/org/iban4j/bban/BbanStructureEntryTest.java
@@ -1,11 +1,12 @@
 package org.iban4j.bban;
 
+import org.junit.jupiter.api.Test;
+
 import java.nio.CharBuffer;
 import java.util.Objects;
 import java.util.Random;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -15,27 +16,33 @@ public class BbanStructureEntryTest {
     public void expectRandomAccountNumberIsDeterministicWhenSeeded() {
         BbanStructureEntry entry = BbanStructureEntry.accountNumber(10, 'a');
 
-        assertSeededRandomBbanStructureEntryEquals(entry, "RAHJMYUWWK", 1);
-        assertSeededRandomBbanStructureEntryEquals(entry, "SGAVREIZNE", 2);
-        assertSeededRandomBbanStructureEntryEquals(entry, "SMMHQUVGJX", 3);
+        assertAll(
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "GYNPNTQMPP", 1),
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "ZBFUFVOHNJ", 2),
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "FHTOSEFCAR", 3)
+        );
     }
 
     @Test
     public void expectRandomOwnerAccountNumberIsDeterministicWhenSeeded() {
         BbanStructureEntry entry = BbanStructureEntry.ownerAccountNumber(11, 'n');
 
-        assertSeededRandomBbanStructureEntryEquals(entry, "58734446889", 1);
-        assertSeededRandomBbanStructureEntryEquals(entry, "82079069784", 2);
-        assertSeededRandomBbanStructureEntryEquals(entry, "40018294915", 3);
+        assertAll(
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "88511786533", 1),
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "33705581952", 2),
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "13164650831", 3)
+        );
     }
 
     @Test
     public void expectRandomBankCodeIsDeterministicWhenSeeded() {
         BbanStructureEntry entry = BbanStructureEntry.bankCode(12, 'c');
 
-        assertSeededRandomBbanStructureEntryEquals(entry, "XSJXQ4EAASPP", 1);
-        assertSeededRandomBbanStructureEntryEquals(entry, "4OKJX66R7O22", 2);
-        assertSeededRandomBbanStructureEntryEquals(entry, "EK6POILGJDLA", 3);
+        assertAll(
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "88FV9Z62HZ1T", 1),
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "T7F8TRELZ3I9", 2),
+            () -> assertSeededRandomBbanStructureEntryEquals(entry, "TXTOAA7SCPXB", 3)
+        );
     }
 
     private static void assertSeededRandomBbanStructureEntryEquals(
@@ -119,7 +126,7 @@ public void expectAlphabeticEntryGeneratesAllUppercaseLetters() {
         String distinctChars = getDistinctSortedChars(generated);
 
         assertEquals(
-                    "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+            "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
             distinctChars
         );
     }