Simplify gas estimate actions and add local estimateGasPriceFromRecentBlocks method.

13 files changed, 203 insertions, 55 deletions

diff --git a/ui/app/actions.js b/ui/app/actions.js
index bec9a8cfb..70ec3aed8 100644
--- a/ui/app/actions.js
+++ b/ui/app/actions.js
@@ -6,6 +6,8 @@ const {
   calcGasTotal,
   getParamsForGasEstimate,
   calcTokenBalance,
+  estimateGas,
+  estimateGasPriceFromRecentBlocks,
 } = require('./components/send_/send.utils')
 const ethUtil = require('ethereumjs-util')
 const { fetchLocale } = require('../i18n-helper')
@@ -160,9 +162,6 @@ var actions = {
   updateTransactionParams,
   UPDATE_TRANSACTION_PARAMS: 'UPDATE_TRANSACTION_PARAMS',
   // send screen
-  estimateGas,
-  getGasEstimate,
-  getGasPrice,
   UPDATE_GAS_LIMIT: 'UPDATE_GAS_LIMIT',
   UPDATE_GAS_PRICE: 'UPDATE_GAS_PRICE',
   UPDATE_GAS_TOTAL: 'UPDATE_GAS_TOTAL',
@@ -705,22 +704,6 @@ function signTx (txData) {
   }
 }
 
-function estimateGas (params = {}) {
-  return (dispatch) => {
-    return new Promise((resolve, reject) => {
-      global.ethQuery.estimateGas(params, (err, data) => {
-        if (err) {
-          dispatch(actions.displayWarning(err.message))
-          return reject(err)
-        }
-        dispatch(actions.hideWarning())
-        dispatch(actions.setGasLimit(data))
-        return resolve(data)
-      })
-    })
-  }
-}
-
 function setGasLimit (gasLimit) {
   return {
     type: actions.UPDATE_GAS_LIMIT,
@@ -728,22 +711,6 @@ function setGasLimit (gasLimit) {
   }
 }
 
-function getGasPrice () {
-  return (dispatch) => {
-    return new Promise((resolve, reject) => {
-      global.ethQuery.gasPrice((err, data) => {
-        if (err) {
-          dispatch(actions.displayWarning(err.message))
-          return reject(err)
-        }
-        dispatch(actions.hideWarning())
-        dispatch(actions.setGasPrice(data))
-        return resolve(data)
-      })
-    })
-  }
-}
-
 function setGasPrice (gasPrice) {
   return {
     type: actions.UPDATE_GAS_PRICE,
@@ -758,22 +725,18 @@ function setGasTotal (gasTotal) {
   }
 }
 
-function getGasEstimate ({ selectedAddress, selectedToken, data }) {
+function updateGasData ({ recentBlocks, selectedAddress, selectedToken, data }) {
   return (dispatch) => {
     const estimateGasParams = getParamsForGasEstimate(selectedAddress, selectedToken, data)
     return Promise.all([
-      dispatch(actions.getGasPrice()),
-      dispatch(actions.estimateGas(estimateGasParams)),
+      Promise.resolve(estimateGasPriceFromRecentBlocks(recentBlocks)),
+      estimateGas(estimateGasParams),
     ])
     .then(([gasPrice, gas]) => {
+      dispatch(actions.setGasPrice(gasPrice))
+      dispatch(actions.setGasLimit(gas))
       return calcGasTotal(gas, gasPrice)
     })
-  }
-}
-
-function updateGasData ({ selectedAddress, selectedToken, data }) {
-  return (dispatch) => {
-    return dispatch(actions.getGasEstimate({ selectedAddress, selectedToken, data }))
     .then((gasEstimate) => {
       dispatch(actions.setGasTotal(gasEstimate))
       dispatch(updateSendErrors({ gasLoadingError: null }))
diff --git a/ui/app/components/customize-gas-modal/index.js b/ui/app/components/customize-gas-modal/index.js
index 9ab785760..6637d412a 100644
--- a/ui/app/components/customize-gas-modal/index.js
+++ b/ui/app/components/customize-gas-modal/index.js
@@ -67,7 +67,7 @@ function mapDispatchToProps (dispatch) {
     hideModal: () => dispatch(actions.hideModal()),
     setGasPrice: newGasPrice => dispatch(actions.setGasPrice(newGasPrice)),
     setGasLimit: newGasLimit => dispatch(actions.setGasLimit(newGasLimit)),
-    updateGasData: newGasTotal => dispatch(actions.setGasTotal(newGasTotal)),
+    setGasTotal: newGasTotal => dispatch(actions.setGasTotal(newGasTotal)),
     updateSendAmount: newAmount => dispatch(actions.updateSendAmount(newAmount)),
     updateSendErrors: error => dispatch(updateSendErrors(error)),
   }
@@ -112,7 +112,7 @@ CustomizeGasModal.prototype.save = function (gasPrice, gasLimit, gasTotal) {
     setGasPrice,
     setGasLimit,
     hideModal,
-    updateGasData,
+    setGasTotal,
     maxModeOn,
     selectedToken,
     balance,
@@ -131,7 +131,7 @@ CustomizeGasModal.prototype.save = function (gasPrice, gasLimit, gasTotal) {
 
   setGasPrice(ethUtil.addHexPrefix(gasPrice))
   setGasLimit(ethUtil.addHexPrefix(gasLimit))
-  updateGasData(ethUtil.addHexPrefix(gasTotal))
+  setGasTotal(ethUtil.addHexPrefix(gasTotal))
   updateSendErrors({ insufficientFunds: false })
   hideModal()
 }
diff --git a/ui/app/components/send/currency-display.js b/ui/app/components/send/currency-display.js
index 90fb2b66c..52dc56cb0 100644
--- a/ui/app/components/send/currency-display.js
+++ b/ui/app/components/send/currency-display.js
@@ -5,6 +5,7 @@ const CurrencyInput = require('../currency-input')
 const { conversionUtil, multiplyCurrencies } = require('../../conversion-util')
 const currencyFormatter = require('currency-formatter')
 const currencies = require('currency-formatter/currencies')
+const ethUtil = require('ethereumjs-util')
 
 module.exports = CurrencyDisplay
 
@@ -35,18 +36,17 @@ CurrencyDisplay.prototype.getAmount = function (value) {
 
 CurrencyDisplay.prototype.getValueToRender = function () {
   const { selectedToken, conversionRate, value } = this.props
-
   const { decimals, symbol } = selectedToken || {}
   const multiplier = Math.pow(10, Number(decimals || 0))
 
   return selectedToken
-    ? conversionUtil(value, {
+    ? conversionUtil(ethUtil.addHexPrefix(value), {
       fromNumericBase: 'hex',
       toCurrency: symbol,
       conversionRate: multiplier,
       invertConversionRate: true,
     })
-    : conversionUtil(value, {
+    : conversionUtil(ethUtil.addHexPrefix(value), {
       fromNumericBase: 'hex',
       toNumericBase: 'dec',
       fromDenomination: 'WEI',
diff --git a/ui/app/components/send_/send.component.js b/ui/app/components/send_/send.component.js
index 21e1de09b..438923ab3 100644
--- a/ui/app/components/send_/send.component.js
+++ b/ui/app/components/send_/send.component.js
@@ -28,6 +28,7 @@ export default class SendTransactionScreen extends PersistentForm {
     history: PropTypes.object,
     network: PropTypes.string,
     primaryCurrency: PropTypes.string,
+    recentBlocks: PropTypes.array,
     selectedAddress: PropTypes.string,
     selectedToken: PropTypes.object,
     tokenBalance: PropTypes.string,
@@ -43,6 +44,7 @@ export default class SendTransactionScreen extends PersistentForm {
       editingTransactionId,
       gasLimit,
       gasPrice,
+      recentBlocks,
       selectedAddress,
       selectedToken = {},
       updateAndSetGasTotal,
@@ -53,6 +55,7 @@ export default class SendTransactionScreen extends PersistentForm {
       editingTransactionId,
       gasLimit,
       gasPrice,
+      recentBlocks,
       selectedAddress,
       selectedToken,
     })
diff --git a/ui/app/components/send_/send.constants.js b/ui/app/components/send_/send.constants.js
index b59fcaaf0..e911a5510 100644
--- a/ui/app/components/send_/send.constants.js
+++ b/ui/app/components/send_/send.constants.js
@@ -28,6 +28,13 @@ const NEGATIVE_ETH_ERROR = 'negativeETH'
 const INVALID_RECIPIENT_ADDRESS_ERROR = 'invalidAddressRecipient'
 const REQUIRED_ERROR = 'required'
 
+const ONE_GWEI_IN_WEI_HEX = ethUtil.addHexPrefix(conversionUtil('0x1', {
+  fromDenomination: 'GWEI',
+  toDenomination: 'WEI',
+  fromNumericBase: 'hex',
+  toNumericBase: 'hex',
+}))
+
 module.exports = {
   INSUFFICIENT_FUNDS_ERROR,
   INSUFFICIENT_TOKENS_ERROR,
@@ -39,6 +46,7 @@ module.exports = {
   MIN_GAS_PRICE_HEX,
   MIN_GAS_TOTAL,
   NEGATIVE_ETH_ERROR,
+  ONE_GWEI_IN_WEI_HEX,
   REQUIRED_ERROR,
   TOKEN_TRANSFER_FUNCTION_SIGNATURE,
 }
diff --git a/ui/app/components/send_/send.container.js b/ui/app/components/send_/send.container.js
index df28caca8..879aef87c 100644
--- a/ui/app/components/send_/send.container.js
+++ b/ui/app/components/send_/send.container.js
@@ -10,6 +10,7 @@ import {
   getGasPrice,
   getGasTotal,
   getPrimaryCurrency,
+  getRecentBlocks,
   getSelectedAddress,
   getSelectedToken,
   getSelectedTokenContract,
@@ -53,6 +54,7 @@ function mapStateToProps (state) {
     gasTotal: getGasTotal(state),
     network: getCurrentNetwork(state),
     primaryCurrency: getPrimaryCurrency(state),
+    recentBlocks: getRecentBlocks(state),
     selectedAddress: getSelectedAddress(state),
     selectedToken: getSelectedToken(state),
     tokenBalance: getTokenBalance(state),
@@ -68,12 +70,12 @@ function mapDispatchToProps (dispatch) {
       editingTransactionId,
       gasLimit,
       gasPrice,
+      recentBlocks,
       selectedAddress,
       selectedToken,
     }) => {
-      console.log(`editingTransactionId`, editingTransactionId)
       !editingTransactionId
-        ? dispatch(updateGasData({ selectedAddress, selectedToken, data }))
+        ? dispatch(updateGasData({ recentBlocks, selectedAddress, selectedToken, data }))
         : dispatch(setGasTotal(calcGasTotal(gasLimit, gasPrice)))
     },
     updateSendTokenBalance: ({ selectedToken, tokenContract, address }) => {
diff --git a/ui/app/components/send_/send.selectors.js b/ui/app/components/send_/send.selectors.js
index c5ae1ab7f..850328e10 100644
--- a/ui/app/components/send_/send.selectors.js
+++ b/ui/app/components/send_/send.selectors.js
@@ -3,6 +3,9 @@ const abi = require('human-standard-token-abi')
 const {
   multiplyCurrencies,
 } = require('../../conversion-util')
+const {
+  estimateGasPriceFromRecentBlocks,
+} = require('./send.utils')
 
 const selectors = {
   accountsWithSendEtherInfoSelector,
@@ -18,8 +21,10 @@ const selectors = {
   getForceGasMin,
   getGasLimit,
   getGasPrice,
+  getGasPriceFromRecentBlocks,
   getGasTotal,
   getPrimaryCurrency,
+  getRecentBlocks,
   getSelectedAccount,
   getSelectedAddress,
   getSelectedIdentity,
@@ -124,6 +129,10 @@ function getGasPrice (state) {
   return state.metamask.send.gasPrice
 }
 
+function getGasPriceFromRecentBlocks (state) {
+  return estimateGasPriceFromRecentBlocks(state.metamask.recentBlocks)
+}
+
 function getGasTotal (state) {
   return state.metamask.send.gasTotal
 }
@@ -133,6 +142,10 @@ function getPrimaryCurrency (state) {
   return selectedToken && selectedToken.symbol
 }
 
+function getRecentBlocks (state) {
+  return state.metamask.recentBlocks
+}
+
 function getSelectedAccount (state) {
   const accounts = state.metamask.accounts
   const selectedAddress = getSelectedAddress(state)
diff --git a/ui/app/components/send_/send.utils.js b/ui/app/components/send_/send.utils.js
index 1c7fd2b42..6055c98b1 100644
--- a/ui/app/components/send_/send.utils.js
+++ b/ui/app/components/send_/send.utils.js
@@ -12,12 +12,15 @@ const {
   INSUFFICIENT_FUNDS_ERROR,
   INSUFFICIENT_TOKENS_ERROR,
   NEGATIVE_ETH_ERROR,
+  ONE_GWEI_IN_WEI_HEX,
 } = require('./send.constants')
 const abi = require('ethereumjs-abi')
 
 module.exports = {
   calcGasTotal,
   doesAmountErrorRequireUpdate,
+  estimateGas,
+  estimateGasPriceFromRecentBlocks,
   generateTokenTransferData,
   getAmountErrorObject,
   getParamsForGasEstimate,
@@ -179,6 +182,17 @@ function doesAmountErrorRequireUpdate ({
   return amountErrorRequiresUpdate
 }
 
+function estimateGas (params = {}) {
+  return new Promise((resolve, reject) => {
+    global.ethQuery.estimateGas(params, (err, data) => {
+      if (err) {
+        return reject(err)
+      }
+      return resolve(data)
+    })
+  })
+}
+
 function generateTokenTransferData (selectedAddress, selectedToken) {
   if (!selectedToken) return
   console.log(`abi.rawEncode`, abi.rawEncode)
@@ -187,3 +201,26 @@ function generateTokenTransferData (selectedAddress, selectedToken) {
     x => ('00' + x.toString(16)).slice(-2)
   ).join('')
 }
+
+function hexComparator (a, b) {
+  return conversionGreaterThan(
+    { value: a, fromNumericBase: 'hex' },
+    { value: b, fromNumericBase: 'hex' },
+  ) ? 1 : -1
+}
+
+function estimateGasPriceFromRecentBlocks (recentBlocks) {
+  // Return 1 gwei if no blocks have been observed:
+  if (!recentBlocks || recentBlocks.length === 0) {
+    return ONE_GWEI_IN_WEI_HEX
+  }
+  const lowestPrices = recentBlocks.map((block) => {
+    if (!block.gasPrices || block.gasPrices.length < 1) {
+      return ONE_GWEI_IN_WEI_HEX
+    }
+    return block.gasPrices
+      .sort(hexComparator)[0]
+  })
+  .sort(hexComparator)
+  return lowestPrices[Math.floor(lowestPrices.length / 2)]
+}
diff --git a/ui/app/components/send_/tests/send-component.test.js b/ui/app/components/send_/tests/send-component.test.js
index 4aa1978e4..780ee1046 100644
--- a/ui/app/components/send_/tests/send-component.test.js
+++ b/ui/app/components/send_/tests/send-component.test.js
@@ -42,6 +42,7 @@ describe.only('Send Component', function () {
       history={{ mockProp: 'history-abc'}}
       network={'3'}
       primaryCurrency={'mockPrimaryCurrency'}
+      recentBlocks={['mockBlock']}
       selectedAddress={'mockSelectedAddress'}
       selectedToken={'mockSelectedToken'}
       tokenBalance={'mockTokenBalance'}
@@ -211,6 +212,7 @@ describe.only('Send Component', function () {
           editingTransactionId: 'mockEditingTransactionId',
           gasLimit: 'mockGasLimit',
           gasPrice: 'mockGasPrice',
+          recentBlocks: ['mockBlock'],
           selectedAddress: 'mockSelectedAddress',
           selectedToken: 'mockSelectedToken',
         }
diff --git a/ui/app/components/send_/tests/send-container.test.js b/ui/app/components/send_/tests/send-container.test.js
index e589cca05..2129709c1 100644
--- a/ui/app/components/send_/tests/send-container.test.js
+++ b/ui/app/components/send_/tests/send-container.test.js
@@ -32,6 +32,7 @@ proxyquire('../send.container.js', {
     getGasPrice: (s) => `mockGasPrice:${s}`,
     getGasTotal: (s) => `mockGasTotal:${s}`,
     getPrimaryCurrency: (s) => `mockPrimaryCurrency:${s}`,
+    getRecentBlocks: (s) => `mockRecentBlocks:${s}`,
     getSelectedAddress: (s) => `mockSelectedAddress:${s}`,
     getSelectedToken: (s) => `mockSelectedToken:${s}`,
     getSelectedTokenContract: (s) => `mockTokenContract:${s}`,
@@ -66,6 +67,7 @@ describe('send container', () => {
         gasTotal: 'mockGasTotal:mockState',
         network: 'mockNetwork:mockState',
         primaryCurrency: 'mockPrimaryCurrency:mockState',
+        recentBlocks: 'mockRecentBlocks:mockState',
         selectedAddress: 'mockSelectedAddress:mockState',
         selectedToken: 'mockSelectedToken:mockState',
         tokenBalance: 'mockTokenBalance:mockState',
@@ -91,6 +93,7 @@ describe('send container', () => {
         editingTransactionId: '0x2',
         gasLimit: '0x3',
         gasPrice: '0x4',
+        recentBlocks: ['mockBlock'],
         selectedAddress: '0x4',
         selectedToken: { address: '0x1' },
       }
@@ -105,14 +108,14 @@ describe('send container', () => {
       })
 
       it('should dispatch an updateGasData action when editingTransactionId is falsy', () => {
-        const { selectedAddress, selectedToken, data } = mockProps
+        const { selectedAddress, selectedToken, data, recentBlocks } = mockProps
         mapDispatchToPropsObject.updateAndSetGasTotal(
-          Object.assign(mockProps, {editingTransactionId: false})
+          Object.assign({}, mockProps, {editingTransactionId: false})
         )
         assert(dispatchSpy.calledOnce)
         assert.deepEqual(
           actionSpies.updateGasData.getCall(0).args[0],
-          { selectedAddress, selectedToken, data }
+          { selectedAddress, selectedToken, data, recentBlocks }
         )
       })
     })
diff --git a/ui/app/components/send_/tests/send-selectors-test-data.js b/ui/app/components/send_/tests/send-selectors-test-data.js
index ecfe9022f..a1423675d 100644
--- a/ui/app/components/send_/tests/send-selectors-test-data.js
+++ b/ui/app/components/send_/tests/send-selectors-test-data.js
@@ -198,6 +198,7 @@ module.exports = {
       },
     },
     'currentLocale': 'en',
+    recentBlocks: ['mockBlock1', 'mockBlock2', 'mockBlock3'],
   },
   'appState': {
     'menuOpen': false,
diff --git a/ui/app/components/send_/tests/send-selectors.test.js b/ui/app/components/send_/tests/send-selectors.test.js
index 977fe2a47..22e45afdb 100644
--- a/ui/app/components/send_/tests/send-selectors.test.js
+++ b/ui/app/components/send_/tests/send-selectors.test.js
@@ -17,6 +17,7 @@ const {
   getGasPrice,
   getGasTotal,
   getPrimaryCurrency,
+  getRecentBlocks,
   getSelectedAccount,
   getSelectedAddress,
   getSelectedIdentity,
@@ -239,6 +240,15 @@ describe('send selectors', () => {
     })
   })
 
+  describe('getRecentBlocks()', () => {
+    it('should return the recent blocks', () => {
+      assert.deepEqual(
+        getRecentBlocks(mockState),
+        ['mockBlock1', 'mockBlock2', 'mockBlock3']
+      )
+    })
+  })
+
   describe('getSelectedAccount()', () => {
     it('should return the currently selected account', () => {
       assert.deepEqual(
diff --git a/ui/app/components/send_/tests/send-utils.test.js b/ui/app/components/send_/tests/send-utils.test.js
index 903b531e6..b5211a63d 100644
--- a/ui/app/components/send_/tests/send-utils.test.js
+++ b/ui/app/components/send_/tests/send-utils.test.js
@@ -1,6 +1,13 @@
 import assert from 'assert'
 import sinon from 'sinon'
 import proxyquire from 'proxyquire'
+import {
+  ONE_GWEI_IN_WEI_HEX,
+} from '../send.constants'
+const {
+  addCurrencies,
+  subtractCurrencies,
+} = require('../../../conversion-util')
 
 const {
   INSUFFICIENT_FUNDS_ERROR,
@@ -31,7 +38,9 @@ const sendUtils = proxyquire('../send.utils.js', {
 
 const {
   calcGasTotal,
+  estimateGas,
   doesAmountErrorRequireUpdate,
+  estimateGasPriceFromRecentBlocks,
   generateTokenTransferData,
   getAmountErrorObject,
   getParamsForGasEstimate,
@@ -261,4 +270,101 @@ describe('send utils', () => {
     })
   })
 
+  describe('estimateGas', () => {
+    let tempEthQuery
+    beforeEach(() => {
+      tempEthQuery = global.ethQuery
+      global.ethQuery = {
+        estimateGas: sinon.stub().callsFake((data, cb) => {
+          return cb(
+            data.isMockErr ? 'mockErr' : null,
+            Object.assign(data, { estimateGasCalled: true })
+          )
+        })
+      }
+    })
+
+    afterEach(() => {
+      global.ethQuery = tempEthQuery
+    })
+
+    it('should call ethQuery.estimateGas and resolve that call\'s data', async () => {
+      const result = await estimateGas({ mockParam: 'someData' })
+      assert.equal(global.ethQuery.estimateGas.callCount, 1)
+      assert.deepEqual(
+        result,
+        { mockParam: 'someData', estimateGasCalled: true }
+      )
+    })
+
+    it('should reject with ethQuery.estimateGas error', async () => {
+      try {
+        await estimateGas({ mockParam: 'someData', isMockErr: true })
+      } catch (err) {
+        assert.equal(err, 'mockErr')
+      }
+    })
+  })
+
+  describe('estimateGasPriceFromRecentBlocks', () => {
+    const ONE_GWEI_IN_WEI_HEX_PLUS_ONE = addCurrencies(ONE_GWEI_IN_WEI_HEX, '0x1', {
+      aBase: 16,
+      bBase: 16,
+      toNumericBase: 'hex',
+    })
+    const ONE_GWEI_IN_WEI_HEX_PLUS_TWO = addCurrencies(ONE_GWEI_IN_WEI_HEX, '0x2', {
+      aBase: 16,
+      bBase: 16,
+      toNumericBase: 'hex',
+    })
+    const ONE_GWEI_IN_WEI_HEX_MINUS_ONE = subtractCurrencies(ONE_GWEI_IN_WEI_HEX, '0x1', {
+      aBase: 16,
+      bBase: 16,
+      toNumericBase: 'hex',
+    })
+
+    it(`should return ${ONE_GWEI_IN_WEI_HEX} if recentBlocks is falsy`, () => {
+      assert.equal(estimateGasPriceFromRecentBlocks(), ONE_GWEI_IN_WEI_HEX)
+    })
+
+    it(`should return ${ONE_GWEI_IN_WEI_HEX} if recentBlocks is empty`, () => {
+      assert.equal(estimateGasPriceFromRecentBlocks([]), ONE_GWEI_IN_WEI_HEX)
+    })
+
+    it(`should estimate a block's gasPrice as ${ONE_GWEI_IN_WEI_HEX} if it has no gas prices`, () => {
+      const mockRecentBlocks = [
+        { gasPrices: null },
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_PLUS_ONE ] },
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_MINUS_ONE ] },
+      ]
+      assert.equal(estimateGasPriceFromRecentBlocks(mockRecentBlocks), ONE_GWEI_IN_WEI_HEX)
+    })
+
+    it(`should estimate a block's gasPrice as ${ONE_GWEI_IN_WEI_HEX} if it has empty gas prices`, () => {
+      const mockRecentBlocks = [
+        { gasPrices: [] },
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_PLUS_ONE ] },
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_MINUS_ONE ] },
+      ]
+      assert.equal(estimateGasPriceFromRecentBlocks(mockRecentBlocks), ONE_GWEI_IN_WEI_HEX)
+    })
+
+    it(`should return the middle value of all blocks lowest prices`, () => {
+      const mockRecentBlocks = [
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_PLUS_TWO ] },
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_MINUS_ONE ] },
+        { gasPrices: [ ONE_GWEI_IN_WEI_HEX_PLUS_ONE ] },
+      ]
+      assert.equal(estimateGasPriceFromRecentBlocks(mockRecentBlocks), ONE_GWEI_IN_WEI_HEX_PLUS_ONE)
+    })
+
+    it(`should work if a block has multiple gas prices`, () => {
+      const mockRecentBlocks = [
+        { gasPrices: [ '0x1', '0x2', '0x3', '0x4', '0x5' ] },
+        { gasPrices: [ '0x101', '0x100', '0x103', '0x104', '0x102' ] },
+        { gasPrices: [ '0x150', '0x50', '0x100', '0x200', '0x5' ] },
+      ]
+      assert.equal(estimateGasPriceFromRecentBlocks(mockRecentBlocks), '0x5')
+    })
+  })
 })