diff --git a/src/file_consumer.cc b/src/file_consumer.cc
index d2797376..9a05b12e 100644
--- a/src/file_consumer.cc
+++ b/src/file_consumer.cc
@@ -14,14 +14,14 @@ bool operator==(const CXFileUniqueID& a, const CXFileUniqueID& b) {
 
 bool FileConsumerSharedState::Mark(const std::string& file) {
   std::lock_guard<std::mutex> lock(mutex);
-  return files.insert(file).second;
+  return used_files.insert(file).second;
 }
 
 void FileConsumerSharedState::Reset(const std::string& file) {
   std::lock_guard<std::mutex> lock(mutex);
-  auto it = files.find(file);
-  if (it != files.end())
-    files.erase(it);
+  auto it = used_files.find(file);
+  if (it != used_files.end())
+    used_files.erase(it);
 }
 
 FileConsumer::FileConsumer(FileConsumerSharedState* shared_state,
diff --git a/src/file_consumer.h b/src/file_consumer.h
index 6b2b2792..85cb7644 100644
--- a/src/file_consumer.h
+++ b/src/file_consumer.h
@@ -16,7 +16,7 @@ MAKE_HASHABLE(CXFileUniqueID, t.data[0], t.data[1], t.data[2]);
 bool operator==(const CXFileUniqueID& a, const CXFileUniqueID& b);
 
 struct FileConsumerSharedState {
-  mutable std::unordered_set<std::string> files;
+  mutable std::unordered_set<std::string> used_files;
   mutable std::mutex mutex;
 
   // Mark the file as used. Returns true if the file was not previously used.
diff --git a/src/import_pipeline.cc b/src/import_pipeline.cc
index 4da89cfd..0bcac0ad 100644
--- a/src/import_pipeline.cc
+++ b/src/import_pipeline.cc
@@ -625,6 +625,13 @@ TEST_SUITE("ImportPipeline") {
     std::unique_ptr<IIndexer> indexer;
   };
 
+  // FIXME: validate other state like timestamp_manager, etc.
+  // FIXME: add more interesting tests that are not the happy path
+  // FIXME: test
+  //   - IndexMain_DoCreateIndexUpdate
+  //   - IndexMain_LoadPreviousIndex
+  //   - QueryDb_ImportMain
+
   TEST_CASE_FIXTURE(Fixture, "index request with zero results") {
     indexer = IIndexer::MakeTestIndexer({IIndexer::TestEntry{"foo.cc", 0}});
 
@@ -635,6 +642,8 @@ TEST_SUITE("ImportPipeline") {
     PumpOnce();
     REQUIRE(queue->index_request.Size() == 0);
     REQUIRE(queue->do_id_map.Size() == 0);
+
+    REQUIRE(file_consumer_shared.used_files.empty());
   }
 
   TEST_CASE_FIXTURE(Fixture, "one index request") {
@@ -647,6 +656,8 @@ TEST_SUITE("ImportPipeline") {
     PumpOnce();
     REQUIRE(queue->index_request.Size() == 0);
     REQUIRE(queue->do_id_map.Size() == 100);
+
+    REQUIRE(file_consumer_shared.used_files.empty());
   }
 
   TEST_CASE_FIXTURE(Fixture, "multiple index requests") {
@@ -662,5 +673,7 @@ TEST_SUITE("ImportPipeline") {
     }
     REQUIRE(queue->index_request.Size() == 0);
     REQUIRE(queue->do_id_map.Size() == 105);
+
+    REQUIRE(file_consumer_shared.used_files.empty());
   }
 }
diff --git a/src/utils.h b/src/utils.h
index c4d991ce..55e51015 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -55,6 +55,11 @@ std::string StringJoin(const TValues& values) {
   return StringJoinMap(values, [](const std::string& entry) { return entry; });
 }
 
+template <typename TCollection, typename TValue>
+bool ContainsValue(const TCollection& collection, const TValue& value) {
+  return collection.find(value) != collection.end();
+}
+
 // Finds all files in the given folder. This is recursive.
 std::vector<std::string> GetFilesInFolder(std::string folder,
                                           bool recursive,