implement check for existing uppercase character in password

src/main/java/PasswordValidator.java

@@ -1,8 +1,18 @@
+import java.util.regex.Pattern;
+
 public class PasswordValidator {
     int minLength = 6;
+    boolean requireUppercase = true;
+
+    private final Pattern uppercasePattern = Pattern.compile("^(?=.*[A-Z]).+$");
 
     public boolean validate(String password) {
-        return password.length() >= minLength;
+        if (password.length() < minLength) {
+            return false;
+        } else if (requireUppercase && !uppercasePattern.matcher(password).matches()) {
+            return false;
+        }
+        return true;
     }
 
     public int getMinLength() {
@@ -12,4 +22,12 @@ public class PasswordValidator {
     public void setMinLength(int minLength) {
         this.minLength = minLength;
     }
+
+    public boolean isRequireUppercase() {
+        return requireUppercase;
+    }
+
+    public void setRequireUppercase(boolean requireUppercase) {
+        this.requireUppercase = requireUppercase;
+    }
 }

src/test/java/PasswordValidatorTest.java

@@ -11,8 +11,15 @@ class PasswordValidatorTest {
 
         // test minimum password length
         passwordValidator.setMinLength(6);
+        passwordValidator.setRequireUppercase(false);
         assertFalse(passwordValidator.validate("abcde"));
         assertTrue(passwordValidator.validate("abcdef"));
         assertTrue(passwordValidator.validate("abcdefg"));
+
+        // test uppercase requirement
+        passwordValidator.setRequireUppercase(true);
+        assertFalse(passwordValidator.validate("abcdef"));
+        assertTrue(passwordValidator.validate("abCdef"));
+        assertTrue(passwordValidator.validate("ABCDEF"));
     }
 }