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Technology

TestNG

Difficulty

Intermediate

Experience

1-2 Years

Type

Technical

AutomateQA Team

QA Automation Engineers

June 15, 2026

Interview Question

What are some common assertions provided by TestNG?

Q: What are some common assertions provided by TestNG?

Common TestNG Assertions TestNG''s Assert class provides static methods to validate test conditions. A failed assertion throws AssertionError and marks the test as FAILED. Commonly used assertion methods: 1. assertEquals — Check equality: java Assert.assertEquals(actual, expected); Assert.assertEquals(driver.getTitle(), "Home Page"); Assert.assertEquals(actual, expected, "Custom failure message"); // Overloaded for: String, int, double, boolean, Object, etc. 2. assertNotEquals — Check inequality: java Assert.assertNotEquals(actual, notExpected); Assert.assertNotEquals(driver.getTitle(), "Error

TestNG assertions include assertEquals, assertNotEquals, assertTrue, assertFalse, assertNull, assertNotNull, and fail() for validating test conditions.

Answer

Common TestNG Assertions

TestNG''s Assert class provides static methods to validate test conditions. A failed assertion throws AssertionError and marks the test as FAILED.

Commonly used assertion methods:

1. assertEquals — Check equality:

Java

Assert.assertEquals(actual, expected);
Assert.assertEquals(driver.getTitle(), "Home Page");
Assert.assertEquals(actual, expected, "Custom failure message");
// Overloaded for: String, int, double, boolean, Object, etc.

2. assertNotEquals — Check inequality:

Java

Assert.assertNotEquals(actual, notExpected);
Assert.assertNotEquals(driver.getTitle(), "Error Page");

3. assertTrue — Check condition is true:

Java

Assert.assertTrue(condition);
Assert.assertTrue(element.isDisplayed(), "Element should be visible");

4. assertFalse — Check condition is false:

Java

Assert.assertFalse(condition);
Assert.assertFalse(errorMsg.isDisplayed(), "No error should appear");

5. assertNull — Check object is null:

Java

Assert.assertNull(object);
Assert.assertNull(driver.findElements(By.id("popup")).isEmpty() ? null : "popup");

6. assertNotNull — Check object is not null:

Java

Assert.assertNotNull(object);
Assert.assertNotNull(driver.findElement(By.id("username")));

7. fail — Force test failure:

Java

Assert.fail("Test deliberately failed");
Assert.fail("Expected exception was not thrown");

Full example:

Java

@Test
public void validateHomePage() {
    driver.get("https://example.com");

    // Title validation
    Assert.assertEquals(driver.getTitle(), "Example Domain");

    // Element presence
    WebElement heading = driver.findElement(By.tagName("h1"));
    Assert.assertNotNull(heading, "Heading should exist");
    Assert.assertTrue(heading.isDisplayed(), "Heading should be visible");

    // URL check
    Assert.assertFalse(driver.getCurrentUrl().contains("error"));
}

Quick reference table:

Method	Checks
`assertEquals(a, e)`	a equals e
`assertNotEquals(a, n)`	a does not equal n
`assertTrue(condition)`	condition is true
`assertFalse(condition)`	condition is false
`assertNull(obj)`	obj is null
`assertNotNull(obj)`	obj is not null
`fail(msg)`	Always fails the test

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