Test Code coverage to Cover Catch Block

Question

My Apex Class where I'm having a validation rule for duplicate name check in Catch block

 public pagereference save(){      
        try{
            upsert complexity;
            pg = new ApexPages.StandardController(complexity).view();     
            pg.setredirect(true);       
        }catch(exception ex){
            if(ex.getmessage().contains('FIELD_CUSTOM_VALIDATION_EXCEPTION')){
                String[] errorMsg = ex.getMessage().split('FIELD_CUSTOM_VALIDATION_EXCEPTION,');
                String[] errorMsgOnly = errorMsg[1].split(':');
                apexPages.addMessage(new apexPages.Message(ApexPages.Severity.ERROR,+errorMsgOnly[0].trim()));             
            }else{
                apexPages.addMessage(new apexPages.Message(ApexPages.Severity.ERROR,'An unexpected error occurred. Please contact the support group with the error message'+ex.getmessage()));
            } 
            return null; 
        }   
        return pg;
    }

My Test Class to cover the catch block is something like this

static testMethod void productComplexity_Negative(){     
       ProductComplexity__c pc = new ProductComplexity__c(name='test',Market_Segment__c='Small',Product_Type__c='New');
       insert pc;


       try {
        ProductComplexity__c pc1 = new ProductComplexity__c(name='test',Market_Segment__c='Small',Product_Type__c='New');
           insert pc1;
           ApexPages.standardController sc = new Apexpages.StandardController(pc1);
       HBCProductComplexity hpc = new HBCProductComplexity(sc); 
           hpc.Save();         
}catch(DMLException e) {
        system.debug('all ok'+e);
        system.assertEquals(e.getMessage(), e.getMessage());
    }
}

But still I'm unable to cover the catch block.Since I'm inserting pc1 with the same name getting validation error their itself and it is not covering anything in the method

Answer 1

Instead of inserting the record in try block of test class, call save method hpc.Save(); as it would execute DML inside the main class with the upsert statement, thus covering the controller's catch.