How to hydrate a test case in Matchstick - thegraph

Question

I am trying to test some code that tracks transfers of a token. What I am running into is, that I set my sender to start with 20 tokens. However, when my actual code does a Load, it sees that Holder as null, and so gets initialized to 0. The ID of that entity is just the address.
Do I have to do something to like....get them to use the same database or something like that?
Here is my test case. Note that USER_1 is starting with 20 tokens.
test("Can handle new Transfer", () => {
const USER_1 = new Holder("0x11a964a5a0308b2eC87D3e1ab2b1E14Ea00f6974");
USER_1.stellaHolding = BigInt.fromI32(20);
USER_1.save();
const USER_2 = new Holder("0x21a964a5a0308b2eC87D3e1ab2b1E14Ea00f6974")
USER_2.stellaHolding = BigInt.fromI32(0);
USER_2.save();
const newTransferEvent = createNewStellaEvent(Address.fromString(USER_1.id), Address.fromString(USER_2.id), BigInt.fromI32(10));
handleStellaTransfer(newTransferEvent);
const actual = Holder.load(USER_1.id);
if(actual == null){
assert.assertNotNull(false);
return;
}
assert.fieldEquals("Holder", actual.id, "stellaHolding", BigInt.fromI32(10).toString());
})
Here is the function that my test code is calling
export function handleStellaTransfer(event: Transfer): void {
const stella = updateStella(event);
updateReceiver(event, stella);
updateSender(event, stella);
stella.save();
}
And here is the function of interest. Note that the sender is NULL when I load it in.
function updateSender(event: Transfer, stella: Stella): void {
const senderAddr = event.params.from.toHexString();
let sender = Holder.load(senderAddr);
log.info("{}", [senderAddr])
if(sender == null){
log.info("{}", ["This shouldn't happen x2?"])
sender = new Holder(senderAddr);
//Is 0 the right number for this? Double check this later
sender.stellaHolding = BigInt.fromI32(0);
}
log.info("{}", ["Sender"])
log.info("{}", [sender.stellaHolding.toString()])
sender.stellaHolding = sender.stellaHolding.minus(event.params.value);
log.info("{}", [sender.stellaHolding.toString()])
if(! isHolder(sender)){
stella.holders--;
}
sender.lastTransaction = event.block.timestamp;
sender.save();
}