What is Entry and Exit criteria explain in detail?

Entry and Exit criteria's tells:

For each level of testing like Intergration , System and
User acceptance testing, before and after what we need to
do.

Entry criteria for Integration Testing :

1. Testing environment should be ready.
1. All the Unit Test cases should be passed.
2. High level design document should be ready.
2. All the integration Test cases should be ready.

Exit criteria for Integration Testing :

1. All the Defects found during integration testing should
be fixed.
2. All the Integration Test cases should be passed.