diff --git a/MANIFEST.in b/MANIFEST.in
index 8ee7ecc..64c0cf7 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -12,3 +12,7 @@ recursive-include libbrotli/c/include *.c *.h *.cc
 
 # Include test files
 recursive-include test/ *.py
+
+# Include test fixtures and test runner configuration
+recursive-include libbrotli/tests/testdata *
+include tox.ini