Assertion in Selenium WebDriver using TestNg

Prerequisite - Selenium 
Actual result is compared with expected result with the help of Assertion. It means verification is done to check if the state of the application is the same to what we are expecting or not. For creating assertion we are going to use the Assert class provided by TestNG. 

There are two types of Assertion:- 

1. Hard Assertions. 
2. Soft assertions. 

These are explained as following below. 

1. Hard Assertions : 
When any assert statement fails this type of assertion throws an exception immediately and continues with the next test in the test suite. 

Hard Assertion can be of following types:- 

1. assertEquals - 
This is used to compare expected and actual values in the selenium webdriver. The assertion passes with no exception whenever the expected and actual values are same. But, if the actual and expected values are not same then assert fails with an exception and the test is marked as failed. 

Syntax : 

Assert.assertEquals(actual, expected); 

2. assertNotEquals - 
This is just the opposite of assertEquals. The assertion passes with no exception whenever the expected and actual values are not same. But, if the actual and expected values are same then assert fails with an exception and the test is marked as failed. 

Syntax : 

Assert.assertNotEquals(actual, expected, message); 

3. assertTrue - 
This type of assertion is used when you are checking if condition is true. That is when we are dealing with boolean values this assertion is used. Whenever test case passes it returns true and if condition is false then it skips the current method and jumps to next. 

Syntax : 

Assert.assertTrue(condition); 

4. assertFalse - 
It checks if value returned is false or not. Whenever test case passes it aborts the method and gives an exception. 

Syntax : 

Assert.assertFalse(condition); 

5. assertNull - 
This assertion checks if the object is null or not. It aborts the test if object is null and gives an exception. 

Syntax : 

Assert.assertNull(object);

6. assertNotNull - 
This assertion checks if object is null or not. It aborts the test if object is not null that is if object is having any value and gives an exception. 

Syntax : 

Assert.assertNotNull(object); 

2. Soft Assertion : 
These types of Assertions are the type of assertions do not throw an exception when an assertion fails and continues with the next step after the assert statement.