diff --git a/tools/binman/bintool_test.py b/tools/binman/bintool_test.py
index f9b16d4..949d6f4 100644
--- a/tools/binman/bintool_test.py
+++ b/tools/binman/bintool_test.py
@@ -303,6 +303,7 @@
                 # See Bintool.build_from_git()
                 tmpdir = cmd[2]
                 self.fname = os.path.join(tmpdir, 'pathname')
+                os.makedirs(os.path.dirname(tmpdir), exist_ok=True)
                 tools.write_file(self.fname, b'hello')
 
         expected = b'this is a test'