I have to write some code for a Salesforce Enterprise edition that doesn’t allow me to create/modify/drop triggers or Apex classes by using the interface.

I created in Eclipse the class which code is written below. When attempting to save it, I get this message:'Test coverage of selected Apex Class and Trigger is 46%, at least 75% test coverage is required'. I know I’m missing something here, but I cannot realize what.

Can someone help please? Thank you.

global class test_records

{

    WebService static String create_test_records()

    {

        String mystr;

        try

       {

           Account a=new Account(name='test_acc');

           insert a;

           ID a_id=[select id from account where name='test_acc'].id;

           Purchases__c p=new Purchases__c(accountid__c=a_id);

           insert p;

           ID p_id=[select id from purchases__c where accountid__c=:a_id].id;

           PurchaseItems__c i1=new PurchaseItems__c(purchaseid__c=p_id, package__c='Item A', price__c=10, quantity__c=1,

                                                                               Barcode_Email_Status__c='Not Sent',

                                                                               Barcode_Email_Recipient__c='x@y.com');

           insert i1;

           PurchaseItems__c i2=new PurchaseItems__c(purchaseid__c=p_id, package__c='Item B', price__c=20, quantity__c=2,

                                                                              Barcode_Email_Status__c='Not Sent',

                                                                              Barcode_Email_Recipient__c='x@y.com');

            insert i2;

            mystr='done';

       }

       catch (System.DMLException e)

       {

          mystr='dml error';

       }

       return mystr;

    }

    static testMethod void test_create_test_records()

    {

        System.assertEquals('done',create_test_records());

    }

}