Integration Testing

• Testing of combined parts of an application to determine if they function correctly.
• Two ways, Bottom-up integration and Top-Down integration
• Top-Down integration-highest-level modules are tested first and progressively, lower-level modules are tested thereafter.
• Bottom-up integration low-level modules are tested first and progressively, higher-level modules are tested thereafter.
• Integration testing tests interfaces between components.
• After integrating two different components together testers do the integration testing. 

Integration  testing tools

• JUnit
• Nested Runner