Move `confirm()` override into contract module

And simplify its test

ethers/contract.nim

@@ -234,3 +234,21 @@ proc subscribe*[E: Event](contract: Contract,
       handler(event)
 
   contract.provider.subscribe(filter, logHandler)
+
+proc confirm*(tx: Future[?TransactionResponse],
+              confirmations: int = EthersDefaultConfirmations,
+              timeout: int = EthersReceiptTimeoutBlks):
+             Future[TransactionReceipt] {.async.} =
+  ## Convenience method that allows confirm to be chained to a contract
+  ## transaction, eg:
+  ## `await token.connect(signer0)
+  ##          .mint(accounts[1], 100.u256)
+  ##          .confirm(3)`
+
+  without response =? (await tx):
+    raise newException(
+      EthersError,
+      "Transaction hash required. Possibly was a call instead of a send?"
+    )
+
+  return await response.confirm(confirmations, timeout)

ethers/provider.nim

@@ -158,23 +158,5 @@ proc confirm*(tx: Future[TransactionResponse],
   let txResp = await tx
   return await txResp.confirm(confirmations, timeout)
 
-proc confirm*(tx: Future[?TransactionResponse],
-             confirmations: int = EthersDefaultConfirmations,
-             timeout: int = EthersReceiptTimeoutBlks):
-            Future[TransactionReceipt] {.async.} =
-  ## Convenience method that allows wait to be chained to a contract
-  ## transaction, eg:
-  ## `await token.connect(signer0)
-  ##          .mint(accounts[1], 100.u256)
-  ##          .confirm(3)`
-
-  without txResp =? (await tx):
-    raise newException(
-      EthersError,
-      "Transaction hash required. Possibly was a call instead of a send?"
-    )
-
-  return await txResp.confirm(confirmations, timeout)
-
 method close*(provider: Provider) {.async, base.} =
   discard

testmodule/testContracts.nim

@@ -181,20 +181,11 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
       check transfers.len == 1
 
     test "can wait for contract interaction tx to be mined":
-      # must not be awaited so we can get newHeads inside of .wait
-      let futMined = provider.mineBlocks(10)
-
       let signer0 = provider.getSigner(accounts[0])
-      let receipt = await token.connect(signer0)
+      let confirming = token.connect(signer0)
                             .mint(accounts[1], 100.u256)
-                      .confirm(3) # wait for 3 confirmations
-      let endBlock = await provider.getBlockNumber()
-
-      check receipt.blockNumber.isSome # was eventually mined
-
-      # >= 3 because more blocks may have been mined by the time the
-      # check in `.wait` was done.
-      # +1 for the block the tx was mined in
-      check (endBlock - !receipt.blockNumber) + 1 >= 3
-
-      await futMined
+                            .confirm(3)
+      await sleepAsync(100.millis) # wait for tx to be mined
+      await provider.mineBlocks(2) # two additional blocks
+      let receipt = await confirming
+      check receipt.blockNumber.isSome