implement check for existing lowercase character in password

src/main/java/PasswordValidator.java

@@ -3,14 +3,18 @@ import java.util.regex.Pattern;
 public class PasswordValidator {
     int minLength = 6;
     boolean requireUppercase = true;
+    boolean requireLowercase = true;
 
     private final Pattern uppercasePattern = Pattern.compile("^(?=.*[A-Z]).+$");
+    private final Pattern lowercasePattern = Pattern.compile("^(?=.*[a-z]).+$");
 
     public boolean validate(String password) {
         if (password.length() < minLength) {
             return false;
         } else if (requireUppercase && !uppercasePattern.matcher(password).matches()) {
             return false;
+        } else if (requireLowercase && !lowercasePattern.matcher(password).matches()) {
+            return false;
         }
         return true;
     }
@@ -30,4 +34,12 @@ public class PasswordValidator {
     public void setRequireUppercase(boolean requireUppercase) {
         this.requireUppercase = requireUppercase;
     }
+
+    public boolean isRequireLowercase() {
+        return requireLowercase;
+    }
+
+    public void setRequireLowercase(boolean requireLowercase) {
+        this.requireLowercase = requireLowercase;
+    }
 }

src/test/java/PasswordValidatorTest.java

@@ -12,14 +12,23 @@ class PasswordValidatorTest {
         // test minimum password length
         passwordValidator.setMinLength(6);
         passwordValidator.setRequireUppercase(false);
+        passwordValidator.setRequireLowercase(false);
         assertFalse(passwordValidator.validate("abcde"));
         assertTrue(passwordValidator.validate("abcdef"));
         assertTrue(passwordValidator.validate("abcdefg"));
 
         // test uppercase requirement
         passwordValidator.setRequireUppercase(true);
+        passwordValidator.setRequireLowercase(false);
         assertFalse(passwordValidator.validate("abcdef"));
         assertTrue(passwordValidator.validate("abCdef"));
         assertTrue(passwordValidator.validate("ABCDEF"));
+
+        // test lowercase requirement
+        passwordValidator.setRequireUppercase(true);
+        passwordValidator.setRequireLowercase(true);
+        assertFalse(passwordValidator.validate("abcdef"));
+        assertTrue(passwordValidator.validate("abCdef"));
+        assertFalse(passwordValidator.validate("ABCDEF"));
     }
 }