diff --git a/ethers/erc20.nim b/ethers/erc20.nim
index ba86db5..eaaa79c 100644
--- a/ethers/erc20.nim
+++ b/ethers/erc20.nim
@@ -46,17 +46,17 @@ method allowance*(token: Erc20Token,
 
 method transfer*(token: Erc20Token,
                  recipient: Address,
-                 amount: UInt256) {.base, contract.}
+                 amount: UInt256): ?TransactionResponse {.base, contract.}
   ## Moves `amount` tokens from the caller's account to `recipient`.
 
 method approve*(token: Erc20Token,
                 spender: Address,
-                amount: UInt256) {.base, contract.}
+                amount: UInt256): ?TransactionResponse {.base, contract.}
   ## Sets `amount` as the allowance of `spender` over the caller's tokens.
 
 method transferFrom*(token: Erc20Token,
                      spender: Address,
                      recipient: Address,
-                     amount: UInt256) {.base, contract.}
+                     amount: UInt256): ?TransactionResponse {.base, contract.}
   ## Moves `amount` tokens from `from` to `to` using the allowance
   ## mechanism. `amount` is then deducted from the caller's allowance.
diff --git a/testmodule/testContracts.nim b/testmodule/testContracts.nim
index 3c3f4c6..4b7f853 100644
--- a/testmodule/testContracts.nim
+++ b/testmodule/testContracts.nim
@@ -9,7 +9,6 @@ import ./miner
 import ./mocks
 
 type
-
   TestToken = ref object of Erc20Token
 
 method mint(token: TestToken, holder: Address, amount: UInt256): ?TransactionResponse {.base, contract.}
@@ -108,8 +107,8 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
       let signer0 = provider.getSigner(accounts[0])
       let signer1 = provider.getSigner(accounts[1])
       discard await token.connect(signer0).mint(accounts[0], 100.u256)
-      await token.connect(signer0).transfer(accounts[1], 50.u256)
-      await token.connect(signer1).transfer(accounts[2], 25.u256)
+      discard await token.connect(signer0).transfer(accounts[1], 50.u256)
+      discard await token.connect(signer1).transfer(accounts[2], 25.u256)
       check (await token.connect(provider).balanceOf(accounts[0])) == 50.u256
       check (await token.connect(provider).balanceOf(accounts[1])) == 25.u256
       check (await token.connect(provider).balanceOf(accounts[2])) == 25.u256
@@ -150,8 +149,8 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
 
       let subscription = await token.subscribe(Transfer, handleTransfer)
       discard await token.connect(signer0).mint(accounts[0], 100.u256)
-      await token.connect(signer0).transfer(accounts[1], 50.u256)
-      await token.connect(signer1).transfer(accounts[2], 25.u256)
+      discard await token.connect(signer0).transfer(accounts[1], 50.u256)
+      discard await token.connect(signer1).transfer(accounts[2], 25.u256)
 
       check eventually transfers == @[
         Transfer(receiver: accounts[0], value: 100.u256),
@@ -175,7 +174,7 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
       check eventually transfers.len == 1
       await subscription.unsubscribe()
 
-      await token.connect(signer0).transfer(accounts[1], 50.u256)
+      discard await token.connect(signer0).transfer(accounts[1], 50.u256)
       await sleepAsync(100.millis)
 
       check transfers.len == 1
diff --git a/testmodule/testErc20.nim b/testmodule/testErc20.nim
index 359c4e1..4944efc 100644
--- a/testmodule/testErc20.nim
+++ b/testmodule/testErc20.nim
@@ -51,7 +51,7 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
       check (await token.balanceOf(accounts[0])) == 100.u256
       check (await token.balanceOf(accounts[1])) == 0.u256
 
-      await token.transfer(accounts[1], 50.u256)
+      discard await token.transfer(accounts[1], 50.u256)
 
       check (await token.balanceOf(accounts[0])) == 50.u256
       check (await token.balanceOf(accounts[1])) == 50.u256
@@ -63,7 +63,7 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
       check (await token.balanceOf(accounts[0])) == 100.u256
       check (await token.balanceOf(accounts[1])) == 0.u256
 
-      await token.approve(accounts[1], 50.u256)
+      discard await token.approve(accounts[1], 50.u256)
 
       check (await token.allowance(accounts[0], accounts[1])) == 50.u256
       check (await token.balanceOf(accounts[0])) == 100.u256
@@ -83,13 +83,13 @@ for url in ["ws://localhost:8545", "http://localhost:8545"]:
       check (await token.balanceOf(senderAccount)) == 100.u256
       check (await token.balanceOf(receiverAccount)) == 0.u256
 
-      await token.approve(receiverAccount, 50.u256)
+      discard await token.approve(receiverAccount, 50.u256)
 
       check (await token.allowance(senderAccount, receiverAccount)) == 50.u256
       check (await token.balanceOf(senderAccount)) == 100.u256
       check (await token.balanceOf(receiverAccount)) == 0.u256
 
-      await token.connect(receiverAccountSigner).transferFrom(senderAccount, receiverAccount, 50.u256)
+      discard await token.connect(receiverAccountSigner).transferFrom(senderAccount, receiverAccount, 50.u256)
 
       check (await token.balanceOf(senderAccount)) == 50.u256
       check (await token.balanceOf(receiverAccount)) == 50.u256