fixed estimate gas problem

Author: TonioMacaronio

web3swift/Transaction/Classes/EthereumTransaction.swift

@@ -253,6 +253,15 @@ public struct EthereumTransaction: CustomStringConvertible {
         if transactionOptions != nil, transactionOptions!.value != nil {
             tx.value = transactionOptions!.value!
         }
+        // MARK: - Fixing estimate gas problem: gas price param shouldn't be nil
+        if transactionOptions != nil, let gasPricePolicy = transactionOptions!.gasPrice {
+            switch gasPricePolicy {
+            case .manual(let value):
+                tx.gasPrice = value
+            default:
+                tx.gasPrice = BigUInt(1) // 1 wei to fix wrong estimating gas problem
+            }
+        }
         guard var txParams = tx.encodeAsDictionary(from: from) else {return nil}
         if method == .estimateGas || transactionOptions?.gasLimit == nil {
             txParams.gas = nil

web3swift/Web3/Classes/Web3+ReadingTransaction.swift

@@ -71,6 +71,7 @@ public class ReadTransaction {
             optionsForGasEstimation.from = mergedOptions.from
             optionsForGasEstimation.to = mergedOptions.to
             optionsForGasEstimation.value = mergedOptions.value
+            optionsForGasEstimation.gasPrice = mergedOptions.gasPrice
             optionsForGasEstimation.callOnBlock = mergedOptions.callOnBlock
             let promise = self.web3.eth.estimateGasPromise(assembledTransaction, transactionOptions: optionsForGasEstimation)
             promise.done(on: queue) {(estimate: BigUInt) in

web3swiftTests/web3swift_promises_Tests.swift

@@ -55,6 +55,27 @@ class web3swift_promises_Tests: XCTestCase {
         }
     }
 
+    func testEstimateGasFixPromise() {
+        do {
+            let web3 = Web3.InfuraMainnetWeb3()
+            let sendToAddress = EthereumAddress("0xe22b8979739D724343bd002F9f432F5990879901")
+            let tempKeystore = try! EthereumKeystoreV3(password: "")
+            let keystoreManager = KeystoreManager([tempKeystore!])
+            web3.addKeystoreManager(keystoreManager)
+            let contract = web3.contract(Web3.Utils.coldWalletABI, at: sendToAddress, abiVersion: 2)
+            guard let writeTX = contract?.write("fallback") else {return XCTFail()}
+            writeTX.transactionOptions.from = tempKeystore!.addresses?.first
+            writeTX.transactionOptions.value = BigUInt("1.0", .eth)
+            writeTX.transactionOptions.gasPrice = .manual(BigUInt(100000000))
+            let esimate = try writeTX.estimateGasPromise().wait()
+            print(esimate)
+            XCTAssert(esimate == 21000)
+        } catch{
+            print(error)
+            XCTFail()
+        }
+    }
+    
 //    func testSendETHPromise() {
 //        do {
 //            guard let keystoreData = getKeystoreData() else {return}