How do Check the Page Message in Test Code Coverage in Salesforce Apex Class

get the list of Messages Using Below Code,
Example 1:
List<Apexpages.Message> msgs = ApexPages.getMessages();
boolean b = false;
for(Apexpages.Message msg:msgs){
if (msg.getDetail().contains(‘Search requires more characters’)) b = true;
}
system.assert(b);

Example 2:
List<ApexPages.Message> msgList = ApexPages.getMessages();
// or loop over the messages
for(ApexPages.Message msg :  ApexPages.getMessages()) {
System.assertEquals(‘Have a nice day’, msg.getSummary());
System.assertEquals(ApexPages.Severity.ERROR, msg.getSeverity());
}