Merge pull request #1594 from datafaker-net/fix/1593-singapore-id-number

#1593 fix Singapore ID number generation

Author: kingthorin

src/main/java/net/datafaker/idnumbers/SingaporeIdNumber.java

@@ -4,7 +4,6 @@
 import net.datafaker.providers.base.IdNumber.IdNumberRequest;
 import net.datafaker.providers.base.PersonIdNumber;
 import net.datafaker.providers.base.PersonIdNumber.Gender;
-import net.datafaker.service.RandomService;
 
 import java.time.LocalDate;
 
@@ -42,7 +41,7 @@ private static String format(LocalDate issueDate, boolean citizen, int[] randomD
         return id.toString();
     }
 
-    private static final int[] CODE = {0, 2, 7, 6, 5, 4, 3, 2};
+    private static final int[] CODE = {2, 7, 6, 5, 4, 3, 2};
     private static final String FIN_LETTERS = "XWUTRQPNMLK";
     private static final String UIN_LETTERS = "JZIHGFEDCBA";
 
@@ -60,7 +59,7 @@ public PersonIdNumber generateValid(BaseProviders faker, IdNumberRequest request
     }
 
     private static PersonIdNumber generateValidIdNumber(BaseProviders faker, LocalDate birthDate, boolean citizen, Gender gender) {
-        int[] number = randomDigits(faker);
+        int[] number = faker.number().randomDigits(7);
         String idNumber = format(birthDate, citizen, number);
         return new PersonIdNumber(idNumber, birthDate, gender);
     }
@@ -89,15 +88,6 @@ static LocalDate randomBirthDate(BaseProviders faker, Type type) {
         };
     }
 
-    private static int[] randomDigits(BaseProviders f) {
-        final RandomService random = f.random();
-        final int[] number = new int[7];
-        for (int i = 0; i < number.length; i++) {
-            number[i] = random.nextInt(0, 9);
-        }
-        return number;
-    }
-
     static char centuryPrefixCitizen(LocalDate issueDate) {
         int century = issueDate.getYear() / 100;
         return (char) ('A' + century - 1);

src/main/java/net/datafaker/providers/base/Number.java

@@ -23,6 +23,17 @@ public int randomDigit() {
         return faker.random().nextInt(0, 9);
     }
 
+    /**
+     * Returns an array of random numbers from 0 to 9 (both inclusive) of given length
+     */
+    public int[] randomDigits(int length) {
+        int[] result = new int[length];
+        for (int i = 0; i < length; i++) {
+            result[i] = randomDigit();
+        }
+        return result;
+    }
+
     /**
      * Returns a random number from 1-9 (both inclusive)
      */

src/test/java/net/datafaker/providers/base/NumberTest.java

@@ -3,6 +3,8 @@
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 import java.math.BigDecimal;
 import java.util.HashMap;
@@ -40,6 +42,17 @@ void testRandomDigit() {
         assertThat(nums).contains(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
     }
 
+    @ParameterizedTest
+    @ValueSource(ints = {0, 1, 2, 3, 4, 8, 16, 25, 36})
+    void randomDigits(int length) {
+        final Number number = faker.number();
+        int[] value = number.randomDigits(length);
+        assertThat(value).hasSize(length);
+        for (int i = 0; i < length; i++) {
+            assertThat(value[i]).isLessThanOrEqualTo(9).isGreaterThanOrEqualTo(0);
+        }
+    }
+
     @Test
     void testRandomDigitNotZero() {
         Set<Integer> nums = new HashSet<>(10);