implement generating lowercase passwords with a customizable length

src/main/java/PasswordGenerator.java

@@ -1,5 +1,26 @@
+import java.security.SecureRandom;
+
 public class PasswordGenerator {
+
+    final String lowercaseCharacters = "abcdefghjkmnpqrstuvwxyz";
+
+    int length = 12;
+
+    public int getLength() {
+        return length;
+    }
+
+    public void setLength(int length) {
+        this.length = length;
+    }
+
     public String generateRandomPassword() {
-        return "";
+        StringBuilder generatedPassword = new StringBuilder();
+        SecureRandom rand = new SecureRandom();
+
+        for (int generatorPosition = 0; generatorPosition < getLength(); generatorPosition++) {
+            generatedPassword.append(lowercaseCharacters.charAt(rand.nextInt(lowercaseCharacters.length())));
+        }
+        return generatedPassword.toString();
     }
 }

src/test/java/PasswordGeneratorTest.java

@@ -1,6 +1,8 @@
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
+import java.util.regex.Pattern;
+
 import static org.junit.jupiter.api.Assertions.*;
 
 class PasswordGeneratorTest {
@@ -14,6 +16,15 @@ class PasswordGeneratorTest {
 
     @Test
     void generateRandomPassword() {
-        assertSame("", passwordGenerator.generateRandomPassword());
+        assertNotSame("", passwordGenerator.generateRandomPassword());
+        assertEquals(passwordGenerator.generateRandomPassword().length(), passwordGenerator.getLength());
+
+        // test length requirement
+        passwordGenerator.setLength(33);
+        assertEquals(passwordGenerator.getLength(), 33);
+        assertEquals(passwordGenerator.generateRandomPassword().length(), passwordGenerator.getLength());
+
+        // test lowercase requirement
+        assertTrue(Pattern.compile("^(?=.*[a-z]).+$").matcher(passwordGenerator.generateRandomPassword()).matches());
     }
-}
+}