Merge "Test that IpClient does not leak fds on shutdown." am: e0ddb33c

import org.mockito.Spy;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileDescriptor;

import java.io.FileReader;

import java.io.IOException;

        // due to the null V6ONLY_WAIT.

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);

    }

    private static int getNumOpenFds() {

        return new File("/proc/" + Os.getpid() + "/fd").listFiles().length;

    }

    private void shutdownAndRecreateIpClient() throws Exception {

        mIpc.shutdown();

        awaitIpClientShutdown();

        mIpc = makeIpClient();

    }

    @Test

    public void testNoFdLeaks() throws Exception {

        // Shut down and restart IpClient once to ensure that any fds that are opened the first

        // time it runs do not cause the test to fail.

        doDualStackProvisioning();

        shutdownAndRecreateIpClient();

        // Unfortunately we cannot use a large number of iterations as it would make the test run

        // too slowly. On crosshatch-eng each iteration takes ~250ms.

        final int iterations = 10;

        final int before = getNumOpenFds();

        for (int i = 0; i < iterations; i++) {

            doDualStackProvisioning();

            shutdownAndRecreateIpClient();

            // The last time this loop runs, mIpc will be shut down in tearDown.

        }

        final int after = getNumOpenFds();

        // Check that the number of open fds is the same as before.

        // If this exact match becomes flaky, we could add some tolerance here (e.g., allow 2-3

        // extra fds), since it's likely that any leak would at least leak one FD per loop.

        assertEquals("Fd leak after " + iterations + " iterations: ", before, after);

    }

}