add support for gas estimate and calldata from ContractCall (#53)

* add support for gas estimate and calldata from ContractCall

* fix celo tests for get_block and get_tx

ethers-contract/src/call.rs

@@ -1,6 +1,6 @@
 use ethers_core::{
     abi::{Detokenize, Error as AbiError, Function, InvalidOutputType},
-    types::{Address, BlockNumber, TransactionRequest, TxHash, U256},
+    types::{Address, BlockNumber, Bytes, TransactionRequest, TxHash, U256},
 };
 use ethers_providers::{JsonRpcClient, ProviderError};
 use ethers_signers::{Client, ClientError, Signer};
@@ -91,6 +91,16 @@ where
     P: JsonRpcClient,
     D: Detokenize,
 {
+    /// Returns the underlying transaction's ABI encoded data
+    pub fn calldata(&self) -> Option<Bytes> {
+        self.tx.data.clone()
+    }
+
+    /// Returns the estimated gas cost for the underlying transaction to be executed
+    pub async fn estimate_gas(&self) -> Result<U256, ContractError> {
+        Ok(self.client.estimate_gas(&self.tx).await?)
+    }
+
     /// Queries the blockchain via an `eth_call` for the provided transaction.
     ///
     /// If executed on a non-state mutating smart contract function (i.e. `view`, `pure`)

ethers-contract/tests/contract.rs

@@ -46,15 +46,19 @@ mod eth_tests {
         // need to declare the method first, and only then send it
         // this is because it internally clones an Arc which would otherwise
         // get immediately dropped
-        let _tx_hash = contract
+        let contract_call = contract
             .connect(client2.clone())
             .method::<_, H256>("setValue", "hi".to_owned())
-            .unwrap()
-            .send()
-            .await
             .unwrap();
+        let calldata = contract_call.calldata().unwrap();
+        let gas_estimate = contract_call.estimate_gas().await.unwrap();
+        let tx_hash = contract_call.send().await.unwrap();
+        let tx = client.get_transaction(tx_hash).await.unwrap();
+        let tx_receipt = client.get_transaction_receipt(tx_hash).await.unwrap();
         assert_eq!(last_sender.clone().call().await.unwrap(), client2.address());
         assert_eq!(get_value.clone().call().await.unwrap(), "hi");
+        assert_eq!(tx.input, calldata);
+        assert_eq!(tx_receipt.gas_used.unwrap(), gas_estimate);
 
         // we can also call contract methods at other addresses with the `at` call
         // (useful when interacting with multiple ERC20s for example)

ethers-providers/tests/provider.rs

@@ -102,14 +102,14 @@ mod celo_tests {
         let provider =
             Provider::<Http>::try_from("https://alfajores-forno.celo-testnet.org").unwrap();
 
-        let tx_hash = "544ea96cddb16aeeaedaf90885c1e02be4905f3eb43d6db3f28cac4dbe76a625"
+        let tx_hash = "c8496681d0ade783322980cce00c89419fce4b484635d9e09c79787a0f75d450"
             .parse::<H256>()
             .unwrap();
         let tx = provider.get_transaction(tx_hash).await.unwrap();
         assert!(tx.gateway_fee_recipient.is_none());
         assert_eq!(tx.gateway_fee.unwrap(), 0.into());
         assert_eq!(tx.hash, tx_hash);
-        assert_eq!(tx.block_number.unwrap(), 1100845.into())
+        assert_eq!(tx.block_number.unwrap(), 447181.into())
     }
 
     #[tokio::test]
@@ -117,15 +117,15 @@ mod celo_tests {
         let provider =
             Provider::<Http>::try_from("https://alfajores-forno.celo-testnet.org").unwrap();
 
-        let block = provider.get_block(1342561).await.unwrap();
+        let block = provider.get_block(447254).await.unwrap();
         assert_eq!(
             block.randomness,
             Randomness {
-                committed: "a3a64b7a29bb4ddd49b7d9e3cf3dd14ecbb7f0321061706c634d14b15425dd30"
+                committed: "003e12deb86292844274493e9ab6e57ed1e276202c16799d97af723eb0d3253f"
                     .from_hex::<Vec<u8>>()
                     .unwrap()
                     .into(),
-                revealed: "3c5f2f71941783cbe7f2dbd387c35503ca0470b300e1613866b988a1db8902a3"
+                revealed: "1333b3b45e0385da48a01b4459aeda7607867ef6a41167cfdeefa49b9fdce6d7"
                     .from_hex::<Vec<u8>>()
                     .unwrap()
                     .into(),