QuorumPreimage test sometimes fails

[AndrejMitrovic]

Unittesting agora.test.QuorumPreimage..
================================ ASSERT HANDLER ===============================
[source/agora/test/Base.d:1086] Assertion thrown during test: [source/agora/test/QuorumPreimage.d:160] Less than 1 spendables in block:
Height: 19, Prev: 0xa6bd...e299, Root: 0x055b...581e, Enrollments: []
Signature: 0x36ca27541775849c8bc86fcbf79577d1ae89e9c1a68116dd132101f52a2d9f6a0e59146295f78c14f5eeecd094db9ad184a79abdd7d41930671bc657af9cdaa7,
Validators: [252],
Random seed: [0xddfa...75cf],
Slashed validators: [],
Transactions: 1
Type : Freeze, Inputs (1): 0x6071...4a18:0x8482...c7d2
Outputs (2): boa1xza007gl...9g93(30,500,000), boa1xrc00kar...9lkl(30,500,000)
2021-05-12 05:07:06,468 Error [agora.utils.Utility] - Operation timed out: : Request timed-out
Module tests failed: agora.test.QuorumPreimage
----------------

From what I can tell the issue is the usage / implementation of the generateBlocks function. It calls addBlock which internally takes the last block's tx's and tries to spend them. But in the QuorumPreimage test the last block only contains freeze transactions, and those can't be spent.

I'm not even sure how this test didn't always fail.