<p>State-based testing is a powerful technique in software testing that focuses on validating the behavior of a system under test based on its states and transitions at the design phase. This paper presents an effort concerning synchronous and asynchronous testing by generating test cases through a scenario-based approach. Scenario-based testing emphasizes testing the functionalities provided by the system and ensure that all the possible conditions of a scenario are tested by focusing on preconditions, post-conditions and alternative flows, at the design level. The objective is to detect the potential issues associated with the system at the early phase of development. In this work, we analyze state-based faults within the positive scenario (happy path) and other negative scenarios (alternative paths), which are generated from a use case of the system under design. Our approach of test case generation is explained in details through a case study, cart application. The architectural level information such as various unified modeling language diagrams such as use case diagrams, state chart diagrams and sequence diagrams are input to our approach. The state chart diagram is transformed to an intermediate graph acknowledging the events and termed as event dependency graph (EDG). Then, traversing the EDG, test cases are generated. These are the sequences of inputs, execution steps and expected results for verification and validation of the model by analyzing various scenarios within a use case. Our proposed test cases generation approach is efficient in finding most of the seeded state-based faults compared to an existing approach.</p>