updated for listening for events

contracts/AdvancedCollectible.sol

@@ -11,7 +11,9 @@ contract AdvancedCollectible is ERC721, VRFConsumerBase {
     mapping(bytes32 => string) public requestIdToTokenURI;
     mapping(uint256 => Breed) public tokenIdToBreed;
     mapping(bytes32 => uint256) public requestIdToTokenId;
-    event requestedCollectible(bytes32 indexed requestId); 
+    event RequestedCollectible(bytes32 indexed requestId); 
+    // New event from the video!
+    event ReturnedCollectible(bytes32 indexed requestId, uint256 randomNumber);
 
 
     bytes32 internal keyHash;
@@ -32,7 +34,7 @@ contract AdvancedCollectible is ERC721, VRFConsumerBase {
             bytes32 requestId = requestRandomness(keyHash, fee);
             requestIdToSender[requestId] = msg.sender;
             requestIdToTokenURI[requestId] = tokenURI;
-            emit requestedCollectible(requestId);
+            emit RequestedCollectible(requestId);
     }
 
     function fulfillRandomness(bytes32 requestId, uint256 randomNumber) internal override {
@@ -45,6 +47,7 @@ contract AdvancedCollectible is ERC721, VRFConsumerBase {
         tokenIdToBreed[newItemId] = breed;
         requestIdToTokenId[requestId] = newItemId;
         tokenCounter = tokenCounter + 1;
+        emit ReturnedCollectible(requestId, randomNumber);
     }
 
     function setTokenURI(uint256 tokenId, string memory _tokenURI) public {

scripts/advanced_collectible/create_collectible.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python3
 from brownie import AdvancedCollectible, accounts, config
-from scripts.helpful_scripts import get_breed, fund_with_link
+from scripts.helpful_scripts import get_breed, fund_with_link, listen_for_event
 import time
 
 
@@ -12,8 +12,11 @@ def main():
     print("Waiting on second transaction...")
     # wait for the 2nd transaction
     transaction.wait(1)
-    time.sleep(35)
-    requestId = transaction.events["requestedCollectible"]["requestId"]
+    # time.sleep(35)
+    listen_for_event(
+        advanced_collectible, "ReturnedCollectible", timeout=200, poll_interval=10
+    )
+    requestId = transaction.events["RequestedCollectible"]["requestId"]
     token_id = advanced_collectible.requestIdToTokenId(requestId)
     breed = get_breed(advanced_collectible.tokenIdToBreed(token_id))
     print("Dog breed of tokenId {} is {}".format(token_id, breed))

scripts/helpful_scripts.py

@@ -8,8 +8,14 @@
     MockOracle,
     VRFCoordinatorMock,
     Contract,
+    web3,
+    chain,
 )
 import os
+import time
+
+# Set a default gas price
+from brownie.network import priority_fee
 
 OPENSEA_FORMAT = "https://testnets.opensea.io/assets/{}/{}"
 NON_FORKED_LOCAL_BLOCKCHAIN_ENVIRONMENTS = ["hardhat", "development", "ganache"]
@@ -76,12 +82,16 @@ def get_contract(contract_name):
             )
     return contract
 
+
 def get_publish_source():
-    if network.show_active() in LOCAL_BLOCKCHAIN_ENVIRONMENTS or not os.getenv("ETHERSCAN_TOKEN"):
+    if network.show_active() in LOCAL_BLOCKCHAIN_ENVIRONMENTS or not os.getenv(
+        "ETHERSCAN_TOKEN"
+    ):
         return False
-    else: 
+    else:
         return True
 
+
 def get_breed(breed_number):
     switch = {0: "PUG", 1: "SHIBA_INU", 2: "ST_BERNARD"}
     return switch[breed_number]
@@ -112,6 +122,8 @@ def deploy_mocks(decimals=18, initial_value=2000):
     """
     Use this script if you want to deploy mocks to a testnet
     """
+    # Set a default gas price
+    priority_fee("1 gwei")
     print(f"The active network is {network.show_active()}")
     print("Deploying Mocks...")
     account = get_account()
@@ -124,11 +136,44 @@ def deploy_mocks(decimals=18, initial_value=2000):
     print(f"Deployed to {mock_price_feed.address}")
     print("Deploying Mock VRFCoordinator...")
     mock_vrf_coordinator = VRFCoordinatorMock.deploy(
-        link_token.address, {"from": account}
+        link_token.address, {"from": account, "gas_price": chain.base_fee}
     )
     print(f"Deployed to {mock_vrf_coordinator.address}")
 
     print("Deploying Mock Oracle...")
     mock_oracle = MockOracle.deploy(link_token.address, {"from": account})
     print(f"Deployed to {mock_oracle.address}")
     print("Mocks Deployed!")
+
+
+def listen_for_event(brownie_contract, event, timeout=200, poll_interval=2):
+    """Listen for an event to be fired from a contract.
+    We are waiting for the event to return, so this function is blocking.
+
+    Args:
+        brownie_contract ([brownie.network.contract.ProjectContract]):
+        A brownie contract of some kind.
+
+        event ([string]): The event you'd like to listen for.
+
+        timeout (int, optional): The max amount in seconds you'd like to
+        wait for that event to fire. Defaults to 200 seconds.
+
+        poll_interval ([int]): How often to call your node to check for events.
+        Defaults to 2 seconds.
+    """
+    web3_contract = web3.eth.contract(
+        address=brownie_contract.address, abi=brownie_contract.abi
+    )
+    start_time = time.time()
+    current_time = time.time()
+    event_filter = web3_contract.events[event].createFilter(fromBlock="latest")
+    while current_time - start_time < timeout:
+        for event_response in event_filter.get_new_entries():
+            if event in event_response.event:
+                print("Found event!")
+                return event_response
+        time.sleep(poll_interval)
+        current_time = time.time()
+    print("Timeout reached, no event found.")
+    return {"event": None}

tests/integration/test_advanced_int.py

@@ -4,6 +4,7 @@
     get_account,
     get_contract,
     LOCAL_BLOCKCHAIN_ENVIRONMENTS,
+    listen_for_event,
 )
 import time
 
@@ -26,6 +27,9 @@ def test_can_create_advanced_collectible_integration(
     )
     # Act
     advanced_collectible.createCollectible("None", {"from": get_account()})
-    time.sleep(75)
+    # time.sleep(75)
+    listen_for_event(
+        advanced_collectible, "ReturnedCollectible", timeout=200, poll_interval=10
+    )
     # Assert
     assert advanced_collectible.tokenCounter() > 0

tests/unit/test_advanced_collectible.py

@@ -27,7 +27,7 @@ def test_can_create_advanced_collectible(
     transaction_receipt = advanced_collectible.createCollectible(
         "None", {"from": get_account()}
     )
-    requestId = transaction_receipt.events["requestedCollectible"]["requestId"]
+    requestId = transaction_receipt.events["RequestedCollectible"]["requestId"]
     assert isinstance(transaction_receipt.txid, str)
     get_contract("vrf_coordinator").callBackWithRandomness(
         requestId, 777, advanced_collectible.address, {"from": get_account()}

tests/unit/test_simple_collectible.py

@@ -1,11 +1,15 @@
 import pytest
-from brownie import network, SimpleCollectible, convert
+from brownie import network, SimpleCollectible, convert, chain
 from scripts.helpful_scripts import get_account
 
 
 def test_can_create_simple_collectible():
     if network.show_active() not in ["development"] or "fork" in network.show_active():
         pytest.skip("Only for local testing")
-    simple_collectible = SimpleCollectible.deploy({"from": get_account()})
-    simple_collectible.createCollectible("None")
+    simple_collectible = SimpleCollectible.deploy(
+        {"from": get_account(), "gas_price": chain.base_fee}
+    )
+    simple_collectible.createCollectible(
+        "None", {"from": get_account(), "gas_price": chain.base_fee}
+    )
     assert simple_collectible.ownerOf(0) == get_account()