1. A computer-implemented method of automatically generating test script for testing a target system, the method comprising processor performed steps of: receiving a test case flow that includes one or more steps, each step including one or more nodes, each node including one or more sub-nodes, wherein the steps are to be executed sequentially, the nodes of each step are to be executed in parallel, and the sub-nodes of each node are to be executed sequentially, wherein each sub-node is associated with a use-case based application programming interface (UC-API), and wherein each step, node, and sub-node includes a unique identifier; for each sub-node of the test case flow: retrieving a template array corresponding to the UC-API associated with the sub-node; and replacing a first placeholder in the template with the unique identifier of the sub-node to create a unique sub-node array; generating a test array utilizing the test case flow, wherein generating comprises: for each node in a step, generating a node array wherein the elements of each node array includes the sub-node arrays associated with the sub-nodes of the node, and wherein the sub-node arrays are sorted according to an order of the sub-nodes in the node of the test case flow; for each step, generating a step array wherein elements of each step array include references to the node arrays of the nodes in the step; populating the test array wherein each element of the test array includes one of the step arrays.