I've built a custom uploader and I'm struggling to write a test method for it. I was hoping some wouldn't mind helping me out. See Code below.

public class Equipment_CSV_FileUploader
{

    public PageReference reset() {
        return null;
    }

    public string nameFile{get;set;}
    public Blob contentFile{get;set;}
    String[] filelines = new String[]{};
    List<Equipment__c> accstoupload;
    
    public Pagereference ReadFile()
    {
        nameFile=contentFile.toString();
        filelines = nameFile.split('\n');
        accstoupload = new List<Equipment__c>();
        for (Integer i=1;i<filelines.size();i++)
        {
            String[] inputvalues = new String[]{};
            inputvalues = filelines[i].split(',');
            
            Equipment__c a = new Equipment__c();
            a.Name = inputvalues[0];
            a.Receiver_S__c = inputvalues[1];       
            a.Receiver_Model__c = inputvalues[2];
            a.Opportunity__c = ApexPages.currentPage().getParameters().get('oppId');                                  
            
            accstoupload.add(a);         
        }
        try{
        insert accstoupload;
        }
        catch (Exception e)
        {
            ApexPages.Message errormsg = new ApexPages.Message(ApexPages.severity.ERROR,'An error has occured. Please check the template');
            ApexPages.addMessage(errormsg);
        }      
                      
        return null ;
    }
        public List<Equipment__c> getuploadedEquipment()
    {
        if (accstoupload!= NULL)
            if (accstoupload.size() > 0)
                return accstoupload;
            else
                return null;                    
        else
            return null;
    }            
}

This is what I have for a test method so far. I'm at 19% but I really have no idea what I'm doing

@istest
private class Equipment_CSV_FileUploader_TestMethod
{         
    static testmethod void Equipment_CSV_FileUploader_TestMethod()  
    {
        Equipment_CSV_FileUploader testcls = new Equipment_CSV_FileUploader();  
        testcls.ReadFile();
        testcls.reset();                    
    }    
}

Thanks in advance!