Lucene.Net.Index.TestBackwardsCompatibility.TestUpgradeOldSingleSegmentIndexWithAdditions C# (CSharp) Method

        public virtual void TestUpgradeOldSingleSegmentIndexWithAdditions()
        {
            foreach (string name in OldSingleSegmentNames)
            {
                if (VERBOSE)
                {
                    Console.WriteLine("testUpgradeOldSingleSegmentIndexWithAdditions: index=" + name);
                }
                Directory dir = NewDirectory(OldIndexDirs[name]);

                Assert.AreEqual(1, GetNumberOfSegments(dir), "Original index must be single segment");

                // create a bunch of dummy segments
                int id = 40;
                RAMDirectory ramDir = new RAMDirectory();
                for (int i = 0; i < 3; i++)
                {
                    // only use Log- or TieredMergePolicy, to make document addition predictable and not suddenly merge:
                    MergePolicy mp = Random().NextBoolean() ? (MergePolicy)NewLogMergePolicy() : NewTieredMergePolicy();
                    IndexWriterConfig iwc = (new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random()))).SetMergePolicy(mp);
                    IndexWriter w = new IndexWriter(ramDir, iwc);
                    // add few more docs:
                    for (int j = 0; j < RANDOM_MULTIPLIER * Random().Next(30); j++)
                    {
                        AddDoc(w, id++);
                    }
                    w.Dispose(false);
                }

                // add dummy segments (which are all in current
                // version) to single segment index
                MergePolicy mp_ = Random().NextBoolean() ? (MergePolicy)NewLogMergePolicy() : NewTieredMergePolicy();
                IndexWriterConfig iwc_ = (new IndexWriterConfig(TEST_VERSION_CURRENT, null)).SetMergePolicy(mp_);
                IndexWriter iw = new IndexWriter(dir, iwc_);
                iw.AddIndexes(ramDir);
                iw.Dispose(false);

                // determine count of segments in modified index
                int origSegCount = GetNumberOfSegments(dir);

                NewIndexUpgrader(dir).Upgrade();

                int segCount = CheckAllSegmentsUpgraded(dir);
                Assert.AreEqual(origSegCount, segCount, "Index must still contain the same number of segments, as only one segment was upgraded and nothing else merged");

                dir.Dispose();
            }
        }