1. A computer-implemented method for testing a software application in accordance with a test suite, said method comprising: inserting into a test database a description of the test suite for testing the software application being tested (ABT), said ABT programmed to invoke multiple external software applications during execution of at least one test script of the test suite, each external application being replaced by a corresponding simulator such that the ABT invokes at least one of said corresponding simulators during execution of each test script, wherein each test script has been created by a test tool and is associated with a test tool adapter; inserting into the test database output data to be returned to the ABT by each simulator for each execution of each simulator in each test script, and after said inserting the description of the test suite and the output data into the test database, executing each test script of the at least one test script, said executing comprising for a test script of the at least one test script: a test execution engine retrieving details of the test script and of the test tool adapter to which the test script is associated, said test execution engine invoking a simulator controller to set up a simulator context table in the test database with said details of the test script, said test execution engine retrieving the test tool adapter, executing the test script via the test tool adapter being invoked by the test execution engine to initiate execution of the test script and the test tool adapter invoking the test tool that created the test script to perform said execution of the test script, wherein said execution of the test script comprises sending a request, by the ABT to each simulator invoked in the test script of the test suite, for requested data; and receiving, by the ABT, said requested data from each simulator invoked in the test script, wherein the received requested data comprises the output data that had been inserted into the test database prior to said execution of the test script, said test tool adapter using data in the simulator context table to retrieve resulting output that resulted from said execution of the test script, and updating the test database with the resulting output.