implement generating passwords with digits

src/main/java/PasswordGenerator.java

@@ -4,6 +4,7 @@ public class PasswordGenerator {
 
     final String lowercaseCharacters = "abcdefghjkmnpqrstuvwxyz";
     final String uppercaseCharacters = "ABCDEFGHJKMNPQRSTUVWXYZ";
+    final String digits = "0123456789";
 
     int length = 12;
 
@@ -22,6 +23,7 @@ public class PasswordGenerator {
 
         characterPool += lowercaseCharacters;
         characterPool += uppercaseCharacters;
+        characterPool += digits;
 
         for (int generatorPosition = 0; generatorPosition < getLength(); generatorPosition++) {
             generatedPassword.append(characterPool.charAt(rand.nextInt(characterPool.length())));

src/test/java/PasswordGeneratorTest.java

@@ -33,4 +33,9 @@ class PasswordGeneratorTest {
     void testPasswordUppercaseRequirement() {
         assertTrue(Pattern.compile("^(?=.*[A-Z]).+$").matcher(passwordGenerator.generateRandomPassword()).matches());
     }
+
+    @Test
+    void testPasswordDigitsRequirement() {
+        assertTrue(Pattern.compile("^(?=.*\\d).+$").matcher(passwordGenerator.generateRandomPassword()).matches());
+    }
 }