Run JUnit test with external parameter using gradle

I have a Gradle project, in which gradle test (from the Java plugin http://ift.tt/1R8oHWJ) would run JUnit tests.

The test is using a network connection, and I need to pass to the test some hostname, parameter from command line of the test, preferably attached to gradle command line, or otherwise, editing build.gradle file.

How I could pass to my test a certain string?