Integration testing is performed to know whether system's different modules or third party services with system work together correctly or not. Integration Testing is performed by tester only, it comes under the Black Box testing.
We should consider the following points while designing integration test cases from the artifacts (SRS, Use Cases, HLD, LLD etc.):
We should choose the scenarios where data is flowing from one module to another module or from our system to third system.
Change data impact from module to another module or on third party module (services).
Try to choose realistic test data I mean similar to production data.
Condition where data has been changed in module A than its impact on Module B (A-->B).
Condition where data has been changed in module B than its impact on Module A (B-->A).
Scenario what happened if one of the liked module is not available or failed.
How modules are connected to each other?
Knowledge of third party module or services such as:
8.1 How it works ?
8.2 How data has been displayed there?
8.3 Availability of services etc.