diff --git a/coding/coding_tests/file_container_test.cpp b/coding/coding_tests/file_container_test.cpp
index 4e340c55b2..fdb1923171 100644
--- a/coding/coding_tests/file_container_test.cpp
+++ b/coding/coding_tests/file_container_test.cpp
@@ -6,7 +6,7 @@
 #include "../../base/string_utils.hpp"
 
 
-UNIT_TEST(FileContainer_Smoke)
+UNIT_TEST(FilesContainer_Smoke)
 {
   string const fName = "file_container.tmp";
   FileWriter::DeleteFile(fName);
@@ -70,3 +70,73 @@ UNIT_TEST(FileContainer_Smoke)
   }
   FileWriter::DeleteFile(fName);
 }
+
+namespace
+{
+  void CheckInvariant(FilesContainerR & reader, string const & tag, int64_t test)
+  {
+    FileReader r = reader.GetReader(tag);
+    TEST_EQUAL(test, ReadPrimitiveFromPos<int64_t>(r, 0), ());
+  }
+}
+
+UNIT_TEST(FilesContainer_Shared)
+{
+  string const fName = "file_container.tmp";
+  FileWriter::DeleteFile(fName);
+
+  uint32_t const count = 10;
+  int64_t const test64 = 908175281437210836;
+
+  {
+    // shared container fill
+
+    FilesContainerW writer(fName);
+
+    FileWriter w1 = writer.GetWriter("1");
+    WriteToSink(w1, uint32_t(0));
+
+    for (uint32_t i = 0; i < count; ++i)
+      WriteVarUint(w1, i);
+    w1.Flush();
+
+    FileWriter w2 = writer.GetWriter("2");
+    WriteToSink(w2, test64);
+    w2.Flush();
+
+    writer.Finish();
+  }
+
+  {
+    // shared container read and fill
+
+    FilesContainerR reader(fName);
+    FileReader r1 = reader.GetReader("1");
+    uint64_t const offset = sizeof(uint32_t);
+    r1 = r1.SubReader(offset, r1.Size() - offset);
+
+    CheckInvariant(reader, "2", test64);
+
+    FilesContainerW writer(fName, FileWriter::OP_APPEND);
+    FileWriter w = writer.GetWriter("3");
+
+    ReaderSource<FileReader> src(r1);
+    for (uint32_t i = 0; i < count; ++i)
+    {
+      uint32_t test = ReadVarUint<uint32_t>(src);
+      TEST_EQUAL(test, i, ());
+      WriteVarUint(w, i);
+    }
+
+    w.Flush();
+    writer.Finish();
+  }
+
+  {
+    // check invariant
+    FilesContainerR reader(fName);
+    CheckInvariant(reader, "2", test64);
+  }
+
+  FileWriter::DeleteFile(fName);
+}