An assert statement contains a boolean expression where this condition must hold true for the test execution to continue. Thus, execution of the assertion causes evaluation of the boolean expression and an error is reported if the expression evaluates as false.
Assert statement in Manual view
Open a test case in Manual view, then navigate to Assert Statements from command toolbar.
A test step represents assert expression is added to the test case.
Double click on the Input cell to edit the assertion.
Once a test step is added as Assert Statement, it will not be allowed to change into another keyword.
Assert statement in Scripting view
The Script view of test cases allows you to programmatically define and handle assertions easily using either Groovy or Java language. Refer to http://docs.groovy-lang.org/docs/latest/html/documentation/core-testing-guide.html for more details regarding assertions in Groovy.