Is there a convention to distinguish Python integration tests from unit tests?

In our project we have unit tests inside each package, same as your case, and integration tests ,system tests, as a separate package on top level, i.e:

package_1/
  __init__.py
  module_1.py
  module_n.py
  test/
    __init__.py
    test_module_1.py
    test_module_n.py
package_n/
  __init__.py
  module_1.py
  module_n.py
  test/
    __init__.py
    test_module_1.py
    test_module_n.py
systemtest/
  __init__.py
  systemtest_1.py
  systemtest_n.py

I would use this convention even if you’ve got only one package in project. However I am not sure if this is a standard convention, or not.