1. A testing system for testing end-to-end performance conditions of a live multi-tenant system, the testing system comprising: at least one processor; memory storing program code for testing end-to-end performance conditions of a live multi-tenant system that is hosting shared services for multiple tenants, the program code including: a scheduler configured to generate multiple start commands for starting multiple end-to-end tests of the live multi-tenant system on behalf of the multiple tenants, each start command of the multiple start commands configured to start a respective end-to-end test of the multiple end-to-end tests on behalf of one of the multiple tenants; a controller configured to receive multiple controller commands associated with the multiple start commands, each of the multiple controller commands configured to cause the controller to login as a synthetic tenant user of the one of the multiple tenants and to cause one or more synthetic transaction inputs to be provided to the live multi-tenant system on behalf of the one of the multiple tenants, the live multi-tenant system configured to login the synthetic tenant user of the one of the multiple tenants and in response to the one or more synthetic transaction inputs perform one or more synthetic transactions involving at least one of multiple destinations in the live multi-tenant system, the multiple controller commands including a first controller command configured to login as a first synthetic tenant user and to cause one or more first synthetic transaction inputs to be provided to the live multi-tenant system on behalf of a first tenant, the multiple controller commands including a second controller command configured to login as a second synthetic tenant user and to cause one or more second synthetic transaction inputs to be provided to the live multi-tenant system on behalf of a second tenant, the first synthetic user being dedicated to the first tenant, the second synthetic user being dedicated to the second tenant, the first synthetic user and the second synthetic user being different; and an automated test driver configured to receive the multiple start commands from the scheduler, to execute multiple test scripts for generating the multiple controller commands in response to the multiple start commands, to provide the multiple controller commands to the controller, to obtain multiple test results generated by the live multi-tenant system in response to the multiple synthetic transactions, to evaluate the multiple test results to determine the end-to-end performance conditions of the live multi-tenant system on behalf of the multiple tenants, and to generate one or more alerts upon recognizing an alert trigger condition based upon the evaluating of the multiple test results.