diff --git a/tests/lib.sh b/tests/lib.sh
index 7fd970a..abe84d3 100644
--- a/tests/lib.sh
+++ b/tests/lib.sh
@@ -127,6 +127,10 @@
 }
 
 run_bazel() {
+  # Remove the ninja_build output marker file to communicate to buildbot that this is not a regular Ninja build, and its
+  # output should not be parsed as such.
+  rm -rf out/ninja_build
+
   tools/bazel "$@"
 }