Doc'd the use of --noinput for test database handling.

docs/topics/testing/overview.txt

@@ -151,6 +151,13 @@ You can prevent the test databases from being destroyed by using the
 runs. If the database does not exist, it will first be created. Any migrations
 will also be applied in order to keep it up to date.
 
+As described in the previous section, if a test run is forcefully interrupted,
+the test database may not be destroyed. On the next run, you'll be asked
+whether you want to reuse or destroy the database. Use the :option:`test
+--noinput` option to suppress that prompt and automatically destroy the
+database. This can be useful when running tests on a continuous integration
+server where tests may be interrupted by a timeout, for example.
+
 The default test database names are created by prepending ``test_`` to the
 value of each :setting:`NAME` in :setting:`DATABASES`. When using SQLite, the
 tests will use an in-memory database by default (i.e., the database will be