Custom annotations in Selenium Java - Test Execution Trace

Test Overview

This test uses a custom annotation to mark a Selenium test method. It verifies that the test navigates to a webpage, finds a button by its ID, clicks it, and checks the resulting page title.

Test Code - JUnit 5 with Selenium WebDriver

Selenium Java

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import static org.junit.jupiter.api.Assertions.assertEquals;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Retention(RetentionPolicy.RUNTIME)
@interface CustomTest {
}

@ExtendWith(CustomTestExtension.class)
public class CustomAnnotationTest {

    WebDriver driver;

    @CustomTest
    @Test
    public void testButtonClick() {
        driver = new ChromeDriver();
        driver.get("https://example.com");
        WebElement button = driver.findElement(By.id("start-button"));
        button.click();
        String title = driver.getTitle();
        assertEquals("Welcome Page", title);
        driver.quit();
    }
}

// CustomTestExtension would be implemented to process @CustomTest annotations, but is omitted here for brevity.

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts and ChromeDriver is initialized	Browser window opens with a blank page	—	PASS
2	Navigates to https://example.com	Browser displays the example.com homepage with a button having id 'start-button'	—	PASS
3	Finds the button element by id 'start-button'	Button element is located on the page	—	PASS
4	Clicks the button	Page navigates or updates to the Welcome Page	—	PASS
5	Gets the page title	Browser shows the Welcome Page	Check if page title equals 'Welcome Page'	PASS
6	Quits the browser	Browser window closes	—	PASS

Failure Scenario

Failing Condition: Button with id 'start-button' is not found on the page

Execution Trace Quiz - 3 Questions

What does the test verify after clicking the button?

A The button becomes disabled

B The URL changes to a login page

C The page title changes to 'Welcome Page'

D An alert popup appears

Key Result

Using custom annotations can help organize and extend test behavior, but the core Selenium steps like locating elements and assertions remain essential for verifying functionality.

Practice

1. What is the main purpose of creating custom annotations in Selenium Java tests?

easy

A. To automatically generate test reports without any code

B. To replace all Selenium WebDriver methods with custom ones

C. To write test cases without using any Java code

D. To add metadata that can control test behavior or provide extra information

Solution

1. Step 1: Understand what annotations do

   Annotations add metadata to code elements like methods or classes, influencing how tests run or are processed.

2. Step 2: Identify the role of custom annotations

   Custom annotations let testers add their own metadata to control or describe tests beyond built-in annotations.

3. Final Answer:

   To add metadata that can control test behavior or provide extra information -> Option D

4. Quick Check:

   Custom annotations = metadata control [OK]

Hint: Custom annotations add info to tests, not replace code [OK]

Common Mistakes:

• Thinking custom annotations replace WebDriver methods
• Assuming they auto-generate reports without code
• Believing tests can run without Java code

2. Which of the following is the correct syntax to define a custom annotation named TestInfo in Java?

easy

A. public @interface TestInfo { String author(); int priority() default 1; }

B. public class TestInfo { String author(); int priority() default 1; }

C. @interface TestInfo { public String author; public int priority = 1; }

D. annotation TestInfo { String author(); int priority(); }

Solution

1. Step 1: Recall Java annotation syntax

   Annotations use the keyword @interface and define methods without bodies for elements.

2. Step 2: Check public @interface TestInfo { String author(); int priority() default 1; } syntax

   public @interface TestInfo { String author(); int priority() default 1; } correctly uses public @interface TestInfo and defines methods with optional default values.

3. Final Answer:

   public @interface TestInfo { String author(); int priority() default 1; } -> Option A

4. Quick Check:

   Annotation syntax = @interface + methods [OK]

Hint: Annotations use @interface keyword, not class or annotation [OK]

Common Mistakes:

• Using class instead of @interface
• Declaring fields instead of methods inside annotation
• Missing default keyword for optional elements

3. Given the custom annotation and usage below, what will be the output when printTestInfo() is called?

import java.lang.reflect.Method;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Retention(RetentionPolicy.RUNTIME)
@interface TestInfo {
  String author();
  int priority() default 1;
}

public class SampleTest {
  @TestInfo(author = "Alice", priority = 3)
  public void testMethod() {}

  public static void printTestInfo() throws Exception {
    Method m = SampleTest.class.getMethod("testMethod");
    TestInfo info = m.getAnnotation(TestInfo.class);
    System.out.println(info.author() + ":" + info.priority());
  }
}

medium

A. Compilation error

B. Alice:1

C. Alice:3

D. null:0

Solution

1. Step 1: Understand annotation retrieval via reflection

   The method getAnnotation(TestInfo.class) fetches the annotation instance on testMethod.

2. Step 2: Check annotation values

   The annotation has author="Alice" and priority=3, so printing them outputs "Alice:3".

3. Final Answer:

   Alice:3 -> Option C

4. Quick Check:

   Reflection reads annotation values correctly [OK]

Hint: Annotation values print as set, defaults overridden [OK]

Common Mistakes:

• Assuming default priority is used instead of 3
• Expecting null because of missing retention policy
• Thinking reflection causes compile error

4. Consider this custom annotation definition:

@interface TestInfo {
  String author();
  int priority() default 1;
}

And this usage:

@TestInfo(author = "Bob")
public void test() {}

Why might the following code throw a NullPointerException when accessing priority()?

TestInfo info = testMethod.getAnnotation(TestInfo.class);
int p = info.priority();

medium

A. The priority method is missing in the annotation definition

B. The annotation is not retained at runtime, so info is null

C. The author value is missing, causing priority to be null

D. Annotations cannot have default values

Solution

1. Step 1: Check annotation retention policy

   If the annotation lacks @Retention(RetentionPolicy.RUNTIME), it is not available at runtime, so getAnnotation returns null.

2. Step 2: Understand NullPointerException cause

   Since info is null, calling info.priority() throws NullPointerException.

3. Final Answer:

   The annotation is not retained at runtime, so info is null -> Option B

4. Quick Check:

   Missing runtime retention = null annotation [OK]

Hint: Always add @Retention(RetentionPolicy.RUNTIME) for runtime use [OK]

Common Mistakes:

• Assuming default values cause null
• Thinking missing author causes error
• Believing annotations can't have defaults

5. You want to create a custom annotation @StepInfo to mark test steps with a description and an optional severity level (default "LOW"). You also want to process these annotations at runtime to print all step descriptions with their severity. Which combination of annotation elements and retention policy is correct to achieve this?

hard

A. @Retention(RetentionPolicy.RUNTIME) public @interface StepInfo { String description(); String severity() default "LOW"; }

B. @Retention(RetentionPolicy.CLASS) public @interface StepInfo { String description(); String severity() default "LOW"; }

C. @Retention(RetentionPolicy.SOURCE) public @interface StepInfo { String description(); String severity(); }

D. public @interface StepInfo { String description(); String severity() default "LOW"; }

Solution

1. Step 1: Choose correct retention for runtime processing

   To access annotations at runtime via reflection, use @Retention(RetentionPolicy.RUNTIME).

2. Step 2: Define annotation elements with default values

   Define description() as required and severity() with default "LOW" for optional use.

3. Final Answer:

   @Retention(RetentionPolicy.RUNTIME) public @interface StepInfo { String description(); String severity() default "LOW"; } -> Option A

4. Quick Check:

   Runtime retention + default value = correct annotation [OK]

Hint: Use RUNTIME retention to read annotations during tests [OK]

Common Mistakes:

• Using CLASS or SOURCE retention prevents runtime access
• Omitting retention causes default CLASS retention
• Not providing default for optional elements