1. A computer implemented method for identifying missing test scenarios based on a repository of organization-specific in-use scenarios, comprising: accessing a set of scenarios that are actually executed by a specific organization on a data-oriented large-scale software system, referred to as organization-specific in-use scenarios; each organization-specific in-use scenario executes at least two transactions; wherein the organization-specific in-use scenarios are identified by registering the executed transactions and then converting the registered transactions to scenarios utilizing a transaction-to-scenario mapping; comparing the organization-specific in-use scenarios with available test scenarios repairable by a non-programmer user, each available test scenario repairable by a non-programmer user tests at least two transactions, and at least 50% of instructions described in each test scenario repairable by a non-programmer are expressed by user interaction activities; identifying organization-specific in-use scenarios that do not have corresponding test scenarios repairable by a non-programmer user, referred to as first set of missing test scenarios; and providing at least one of the missing test scenarios to a non-programmer user for generating a test scenario repairable by a non-programmer user that covers the at least one missing test scenario and comprises instructions expressed by user interaction activities.