1 files changed, 13 insertions, 2 deletions
diff --git a/src/test.h b/src/test.h
index 37ca1f9..bff0e5a 100644
--- a/src/test.h
+++ b/src/test.h
@@ -41,8 +41,16 @@ void AssertHash(const char* expected, uint64_t actual);
 /// of disk state.  It also logs file accesses and directory creations
 /// so it can be used by tests to verify disk access patterns.
 struct VirtualFileSystem : public DiskInterface {
-  /// "Create" a file with a given mtime and contents.
-  void Create(const string& path, int time, const string& contents);
+  VirtualFileSystem() : now_(1) {}
+
+  /// "Create" a file with contents.
+  void Create(const string& path, const string& contents);
+
+  /// Tick "time" forwards; subsequent file operations will be newer than
+  /// previous ones.
+  int Tick() {
+    return ++now_;
+  }
 
   // DiskInterface
   virtual TimeStamp Stat(const string& path);
@@ -63,6 +71,9 @@ struct VirtualFileSystem : public DiskInterface {
   FileMap files_;
   set<string> files_removed_;
   set<string> files_created_;
+
+  /// A simple fake timestamp for file operations.
+  int now_;
 };
 
 struct ScopedTempDir {