message: Add test for AddTimeData
diff: // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  //
  -#include <timedata.h>
  +
  +#include <netaddress.h>
  +#include <noui.h>
  #include <test/setup_common.h>
  +#include <timedata.h>
  +#include <warnings.h>
  +
  +#include <string>
  #include <boost/test/unit_test.hpp>
  @@ -34,4 +40,61 @@ BOOST_AUTO_TEST_CASE(util_MedianFilter)
  BOOST_CHECK_EQUAL(filter.median(), 7);
  }
  +static void MultiAddTimeData(int n, int64_t offset)
  +{
  + static int cnt = 0;
  + for (int i = 0; i < n; ++i) {
  + CNetAddr addr;
  + addr.SetInternal(std::to_string(++cnt));
  + AddTimeData(addr, offset);
  + }
  +}
  +
  +
  +BOOST_AUTO_TEST_CASE(addtimedata)
  +{
  + BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
  +
  + //Part 1: Add large offsets to test a warning message that our clock may be wrong.
  + MultiAddTimeData(3, DEFAULT_MAX_TIME_ADJUSTMENT + 1);
  + // Filter size is 1 + 3 = 4: It is always initialized with a single element (offset 0)
  +
  + noui_suppress();
  + MultiAddTimeData(1, DEFAULT_MAX_TIME_ADJUSTMENT + 1); //filter size 5
  + noui_reconnect();
  +
  + BOOST_CHECK(GetWarnings("gui").find("clock is wrong") != std::string::npos);
  +
  + // nTimeOffset is not changed if the median of offsets exceeds DEFAULT_MAX_TIME_ADJUSTMENT
  + BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
  +
  + // Part 2: Test positive and negative medians by adding more offsets
  + MultiAddTimeData(4, 100); // filter size 9
  + BOOST_CHECK_EQUAL(GetTimeOffset(), 100);
  + MultiAddTimeData(10, -100); //filter size 19
  + BOOST_CHECK_EQUAL(GetTimeOffset(), -100);
  +
  + // Part 3: Test behaviour when filter has reached maximum number of offsets
  + const int MAX_SAMPLES = 200;
  + int nfill = (MAX_SAMPLES - 3 - 19) / 2; //89
  + MultiAddTimeData(nfill, 100);
  + MultiAddTimeData(nfill, -100); //filter size MAX_SAMPLES - 3
  + BOOST_CHECK_EQUAL(GetTimeOffset(), -100);
  +
  + MultiAddTimeData(2, 100);
  + //filter size MAX_SAMPLES -1, median is the initial 0 offset
  + //since we added same number of positive/negative offsets
  +
  + BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
  +
  + // After the number of offsets has reached MAX_SAMPLES -1 (=199), nTimeOffset will never change
  + // because it is only updated when the number of elements in the filter becomes odd. It was decided
  + // not to fix this because it prevents possible attacks. See the comment in AddTimeData() or issue #4521
  + // for a more detailed explanation.
  + MultiAddTimeData(2, 100); // filter median is 100 now, but nTimeOffset will not change
  + BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
  +
  + // We want this test to end with nTimeOffset==0, otherwise subsequent tests of the suite will fail.
  +}
  +
  BOOST_AUTO_TEST_SUITE_END()
  