The org.jboss.as.test.integration.management.http.HttpDeploymentUploadUnitTestCase uses the java.net.Authenticator.setDefault() to set a default authenticator. This can cause issues with tests that run after this test. The authenticator would be used after when the expectation is for the authentication to fail. This test should be converted to use the Apache HttpClient or at a minimum avoid setting a default authenticator.
It also doesn't look like the test cleans up the deployed content which it should.
Maybe the add-content request could just be moved to the HttpGenericOperationUnitTestCase which has some similar actions. See the HttpGenericOperationUnitTestCase for an example of using the HttpClient for a similar test.