Hi All

I am writing a test class for a Apex class. It only covered 12% of the apex class. Here is my apex class and i mentioned in Red the part of the class covered and the part in blue is not covered. I am new to writing the test classes

public with sharing class accountCreditApprovalController {
  Private string comment = '';
    public String acId= ApexPages.currentPage().getParameters().get('acId');
    public Account_Credit__c ac;
    public accountCreditApprovalController(){
      ac = [select Id, Name, Account__c, Credit_Status__c, Associated_TN__c, Credit_Reason__c,
           Department_Responsible__c, Requested_Credit_Amount__c, Credit_Reason_Comments__c, 
           Account__r.Name from Account_Credit__c where id= :acId];  
    }
    public Account_Credit__c getAc(){
        return ac; 
    }
    public string getComment(){
        return comment;
    }
    public void setComment(string Value){
        comment= Value;
    }
    public PageReference reject1() {
        PageReference pr = null;
        try{        
            ProcessInstanceWorkitem piwi = [Select ProcessInstance.Status, ProcessInstance.TargetObjectId, ProcessInstanceId,OriginalActorId,Id,ActorId From ProcessInstanceWorkitem
            where ProcessInstance.TargetObjectId = : acId and ProcessInstance.Status = 'Pending' and OriginalActorId =: UserInfo.getUserId() order by CreatedDate desc limit 1]; 
            system.debug('---Piwi---' + piwi);
            Approval.ProcessWorkitemRequest req = new Approval.ProcessWorkitemRequest();
            req.setComments(comment);
            req.setAction('Reject');
            req.setWorkitemId(piwi.Id);
            // Submit the request for approval      
            Approval.ProcessResult result =  Approval.process(req);        
            //pr = new PageReference('/home/home.jsp');
            pr = new PageReference('/apex/mobileApprovalList?sfdc.tabName=01r40000000LnKP');
        }
        catch(Exception ex){
            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR,ex.getMessage()));
        }
        return pr;
    }
    public PageReference approve1(){
        PageReference pr = null;
        try{  
            ProcessInstanceWorkitem piwi = [Select ProcessInstance.Status, ProcessInstance.TargetObjectId, ProcessInstanceId,OriginalActorId,Id,ActorId From ProcessInstanceWorkitem
            where ProcessInstance.TargetObjectId = : acId and ProcessInstance.Status = 'Pending' and OriginalActorId =: UserInfo.getUserId() order by CreatedDate desc limit 1];    
            system.debug('---Piwi---' + piwi);
            Approval.ProcessWorkitemRequest req = new Approval.ProcessWorkitemRequest();
            req.setComments(comment);
            req.setAction('Approve');
            req.setWorkitemId(piwi.Id);
            // Submit the request for approval      
            Approval.ProcessResult result =  Approval.process(req);
            //pr = new PageReference('/home/home.jsp');
            pr = new PageReference('/apex/mobileApprovalList?sfdc.tabName=01r40000000LnKP');
        }
        catch(Exception ex){
            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR,ex.getMessage()));
        }
        return pr;
    }     
}

Here is my Test class

}

}