Flaky test "test_aes_gcm_encrypt_decrypt" in test_crypto.c?

[hartwork]

It seems like one of the tests is flaky, at least on Windows:

 [ RUN      ] test_aes_gcm_encrypt_decrypt
[  ERROR   ] --- 0x0 != 0xffffffffffffd8dc
[   LINE   ] --- D:/a/libomemo/libomemo/test/test_crypto.c:79: error: Failure!

Would be cool to understand and become stable.

[hartwork]

It turns out that line…

libomemo/test/test_crypto.c

Line 77 in 6f153c0

ciphertext_p[0] = 0x00;

…has the underlying assumption that the previous value is not already 0. But it can be, and then the test fails.