- Better buffer handling in mpi_read_file()

diff --git a/tests/data_files/mpi_too_big b/tests/data_files/mpi_too_big
new file mode 100644
index 0000000..2d98757
--- /dev/null
+++ b/tests/data_files/mpi_too_big
@@ -0,0 +1 @@
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