public void TestConcurrentAccess() {
            var sourceFiles1 = new[]
                               {
                                   Environment.CurrentDirectory+@"\xyzzy\Example.cs",
                                   Environment.CurrentDirectory+@"\foo\bar\MissingFile.cs",
                                   Environment.CurrentDirectory+@"\zork\Example.cs",
                                   Environment.CurrentDirectory+@"\path\to\file\data.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data1.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data2.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data3.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data4.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data5.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data6.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data7.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data8.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data9.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data10.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data11.c"
                               };
            var sourceFiles2 = new[]
                               {
                                   Environment.CurrentDirectory+@"\foo\bar\Example.cs",
                                   Environment.CurrentDirectory+@"\path\to\file\data.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data1.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data2.cpp",
                                   Environment.CurrentDirectory+@"\foo\bar\ImportantData.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data3.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data4.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data5.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data6.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data7.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data8.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data9.cpp",
                                   Environment.CurrentDirectory+@"\other\dir\Sample.h",
                                   Environment.CurrentDirectory+@"\path\to\file\data10.cpp",
                                   Environment.CurrentDirectory+@"\path\to\file\data11.c"
                               };
            var xmlFiles = new[]
                           {
                               Environment.CurrentDirectory+@"\mappingTest\Example.cs.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\MissingFile.cs.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\Example.cs.2.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data1.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data2.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data3.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data4.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data5.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data6.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data7.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data8.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data9.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data10.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\data11.c.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\Example.cs.3.xml",
                               Environment.CurrentDirectory+@"\mappingTest\ImportantData.cpp.1.xml",
                               Environment.CurrentDirectory+@"\mappingTest\Sample.h.1.xml",
                           };

            var map = new SrcMLFileNameMapping("mappingTest");
            var worker = new Thread(() => ConcurrentWorker(map, sourceFiles2));
            worker.Start();
            foreach(var file in sourceFiles1) {
                map.GetTargetPath(file);
            }
            worker.Join(5000);
            map.SaveMapping();

            var obsSourceFiles = new HashSet<string>();
            var obsXmlFiles = new HashSet<string>();
            foreach(var entry in File.ReadAllLines("mappingTest\\mapping.txt")) {
                var fields = entry.Split('|');
                obsSourceFiles.Add(fields[0]);
                obsXmlFiles.Add(fields[1]);
            }
            var sourceFiles = sourceFiles1.Union(sourceFiles2);
            Assert.AreEqual(sourceFiles.Count(), obsSourceFiles.Count);
            Assert.AreEqual(xmlFiles.Count(), obsXmlFiles.Count);
            foreach(var file in obsSourceFiles) {
                Assert.IsTrue(sourceFiles.Contains(file));
            }
            foreach(var file in obsXmlFiles) {
                Assert.IsTrue(xmlFiles.Contains(file));
            }
        }