refactor minimum password length tests and add getter/setter

src/main/java/PasswordValidator.java

@@ -4,4 +4,12 @@ public class PasswordValidator {
     public boolean validate(String password) {
         return password.length() >= minLength;
     }
+
+    public int getMinLength() {
+        return minLength;
+    }
+
+    public void setMinLength(int minLength) {
+        this.minLength = minLength;
+    }
 }

src/test/java/PasswordValidatorTest.java

@@ -10,6 +10,9 @@ class PasswordValidatorTest {
         assertFalse(passwordValidator.validate(""));
 
         // test minimum password length
+        passwordValidator.setMinLength(6);
+        assertFalse(passwordValidator.validate("abcde"));
         assertTrue(passwordValidator.validate("abcdef"));
+        assertTrue(passwordValidator.validate("abcdefg"));
     }
 }