hello,

         how can i cover try-catch block in test class.

         Controller

public class TestPagecontroller {

            private String firstName;
            private String lastName;
            private String company;
            private String email;
            private String qp;

            public TestPagecontroller () {
                this.qp = ApexPages.currentPage().getParameters().get('qp');
            }

            public String getFirstName() {
                  return this.firstName;
            }

            public void setFirstName(String firstName) {
                  this.firstName = firstName;
            }

            public String getLastName() {
                  return this.lastName;
            }

            public void setLastName(String lastName) {
                  this.lastName = lastName;
            }

            public String getCompany() {
                  return this.company;
            }

            public void setCompany(String company) {
                  this.company = company;
            }

            public String getEmail() {
                  return this.email;
            }

            public void setEmail(String email) {
                  this.email = email;
            }

            public PageReference save() {
                PageReference p = null;
                
                if (this.qp == null || !'yyyy'.equals(this.qp)) {
                    p = Page.failure;
                    p.getParameters().put('error', 'noParam');
                } else {
                    try {
                        Lead newlead = new Lead(LastName=this.lastName,
                                                FirstName=this.firstName,
                                                Company=this.company,
                                                Email=this.email);
                        insert newlead;
                    } catch (Exception e) {
                        p = Page.failure;
                        p.getParameters().put('error', 'noInsert');
                    }
                }
                
                if (p == null) {
                    p = Page.success;
                }
                
                p.setRedirect(true);
                return p;
            }
 }

Test Class

public class thecontrollerTests {

    public static testMethod void testMyController() {
        PageReference pageRef = Page.success;
        Test.setCurrentPage(pageRef);
      
        TestPagecontroller controller = new TestPagecontroller();
        String nextPage = controller.save().getUrl();

        // Verify that page fails without parameters
    
        System.assertEquals('/apex/failure?error=noParam', nextPage);

        // Add parameters to page URL
    
        ApexPages.currentPage().getParameters().put('qp', 'yyyy');
      
        // Instantiate a new controller with all parameters in the page
    
        controller = new TestPagecontroller();
        controller.setLastName('lastname');
        
        controller.setFirstName('firstname');
        controller.setCompany('acme');
        controller.setEmail('firstlast@acme.com');
        System.assertEquals('lastname', controller.getLastName());
        System.assertEquals('firstname', controller.getFirstName());
        System.assertEquals('acme', controller.getCompany());
        System.assertEquals('firstlast@acme.com', controller.getEmail());
        nextPage = controller.save().getUrl();

        // Verify that the success page displays
    
        System.assertEquals('/apex/success', nextPage);
        Lead[] leads = [select id, email from lead where Company = 'acme'];
        System.assertEquals('firstlast@acme.com', leads[0].email);
        
    }
    }

here i am getting 92% Code Coverage. but my test class cant cover catch block.

Plz help me