updated for tests

contracts/Migrations.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.12;
+pragma solidity ^0.6.6;
 
 contract Migrations {
   address public owner;

contracts/MyContract.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.12;
+pragma solidity ^0.6.6;
 
 import "@chainlink/contracts/src/v0.6/ChainlinkClient.sol";
 import "@openzeppelin/contracts/access/Ownable.sol";

contracts/PriceConsumerV3.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.12;
+pragma solidity ^0.6.6;
 
 import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
 
@@ -11,8 +11,8 @@ contract PriceConsumerV3 {
      * Aggregator: ETH/USD
      * Address: 0x9326BFA02ADD2366b30bacB125260Af641031331
      */
-    constructor() public {
-        priceFeed = AggregatorV3Interface(0x9326BFA02ADD2366b30bacB125260Af641031331);
+    constructor(address _priceFeed) public {
+        priceFeed = AggregatorV3Interface(_priceFeed);
     }
 
     /**

contracts/RandomNumberConsumer.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.12;
+pragma solidity ^0.6.6;
 
 import "@chainlink/contracts/src/v0.6/VRFConsumerBase.sol";
 
@@ -8,6 +8,7 @@ contract RandomNumberConsumer is VRFConsumerBase {
     bytes32 internal keyHash;
     uint256 internal fee;
     uint256 public randomResult;
+    event RequestedRandomness(bytes32 requestId);
 
     /**
      * Constructor inherits VRFConsumerBase
@@ -17,22 +18,24 @@ contract RandomNumberConsumer is VRFConsumerBase {
      * LINK token address:                0xa36085F69e2889c224210F603D836748e7dC0088
      * Key Hash: 0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4
      */
-    constructor(address _linkTokenAddress)
+    constructor(address _linkTokenAddress, bytes32 _keyHash, 
+    address _vrfCoordinatorAddress, uint256 _fee)
         public
         VRFConsumerBase(
-            0xdD3782915140c8f3b190B5D67eAc6dc5760C46E9, // VRF Coordinator
+            _vrfCoordinatorAddress, // VRF Coordinator
             _linkTokenAddress  // LINK Token
         )
     {
-        keyHash = 0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4;
-        fee = 0.1 * 10 ** 18; // 0.1 LINK
+        keyHash = _keyHash;
+        fee = _fee;
     }
 
     /** 
      * Requests randomness from a user-provided seed
      */
     function getRandomNumber(uint256 userProvidedSeed) public returns (bytes32 requestId) {
-        return requestRandomness(keyHash, fee, userProvidedSeed);
+        requestId = requestRandomness(keyHash, fee, userProvidedSeed);
+        emit RequestedRandomness(requestId);
     }
 
     /** 

contracts/test/MockV3Aggregator.sol

@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.6.0;
+
+import "@chainlink/contracts/src/v0.6/tests/MockV3Aggregator.sol";

contracts/test/VRFCoordinatorMock.sol

@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.6.0;
+
+import "@chainlink/contracts/src/v0.6/tests/VRFCoordinatorMock.sol";

migrations/3_price_consumer_v3.js

@@ -1,10 +1,14 @@
 const PriceConsumerV3 = artifacts.require('PriceConsumerV3')
+const KOVAN_ETH_USD_PRICE_FEED = '0x9326BFA02ADD2366b30bacB125260Af641031331'
 
 module.exports = async (deployer, network, [defaultAccount]) => {
     // Local (development) networks need their own deployment of the LINK
     // token and the Oracle contract
+
+    // currently hardcoded for Kovan
+    let priceFeedAddress = KOVAN_ETH_USD_PRICE_FEED
     try {
-        await deployer.deploy(PriceConsumerV3, { from: defaultAccount })
+        await deployer.deploy(PriceConsumerV3, KOVAN_ETH_USD_PRICE_FEED, { from: defaultAccount })
     } catch (err) {
         console.error(err)
     }

migrations/4_random_number_consumer.js

@@ -1,19 +1,16 @@
 const RandomNumberConsumer = artifacts.require('RandomNumberConsumer')
-const { LinkToken } = require('@chainlink/contracts/truffle/v0.4/LinkToken')
 
 module.exports = async (deployer, network, [defaultAccount]) => {
     // Local (development) networks need their own deployment of the LINK
     // token and the Oracle contract
     if (!network.startsWith('kovan')) {
-        LinkToken.setProvider(deployer.provider)
-        try {
-            await deployer.deploy(LinkToken, { from: defaultAccount })
-            await deployer.deploy(RandomNumberConsumer, LinkToken.address)
-        } catch (err) {
-            console.error(err)
-        }
+        console.log("only for Kovan right now!")
     } else {
         // For now, this is hard coded to Kovan
-        deployer.deploy(RandomNumberConsumer, '0xa36085F69e2889c224210F603D836748e7dC0088')
+        const KOVAN_KEYHASH = '0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4'
+        const KOVAN_FEE = '100000000000000000'
+        const KOVAN_LINK_TOKEN = '0xa36085F69e2889c224210F603D836748e7dC0088'
+        const KOVAN_VRF_COORDINATOR = '0xdD3782915140c8f3b190B5D67eAc6dc5760C46E9'
+        deployer.deploy(RandomNumberConsumer, KOVAN_LINK_TOKEN, KOVAN_KEYHASH, KOVAN_VRF_COORDINATOR, KOVAN_FEE)
     }
 }

scripts/price-consumer-scripts/get-latest-price.js

@@ -6,7 +6,7 @@ const PriceConsumerV3 = artifacts.require('PriceConsumerV3')
 */
 
 module.exports = async callback => {
-    const priceConsumerV3 = await PriceConsumerV3.deployed()
-    const latestPrice = await priceConsumerV3.getLatestPrice()
-    callback(latestPrice)
+  const priceConsumerV3 = await PriceConsumerV3.deployed()
+  const latestPrice = await priceConsumerV3.getLatestPrice()
+  callback(latestPrice)
 }

test/PriceConsumerV3_test.js

@@ -3,23 +3,28 @@
 This repo is for testing on kovan network only.
 You can get truffle teams and do a forking version of
 these tests.
-
 */
 
+const { assert } = require('chai')
+
 contract('PriceConsumerV3', accounts => {
+    const MockPriceFeed = artifacts.require('MockV3Aggregator')
     const PriceConsumerV3 = artifacts.require('PriceConsumerV3')
 
     const defaultAccount = accounts[0]
     // The addresses here can be found in the chainlink docs
     // https://docs.chain.link/docs/ethereum-addresses
 
-    let priceConsumerV3
+    let priceConsumerV3, mockPriceFeed
 
-    // TODO
     describe('#getLatestPrice', () => {
+        let price = "2000000000000000000"
+        beforeEach(async () => {
+            mockPriceFeed = await MockPriceFeed.new(8, price)
+            priceConsumerV3 = await PriceConsumerV3.new(mockPriceFeed.address)
+        })
         it('returns a price', async () => {
-            priceConsumerV3 = await PriceConsumerV3.new()
-            assert(true, true)
+            assert.equal(await priceConsumerV3.getLatestPrice(), price)
         })
     })
 })

test/RandomNumberConsumer_test.js

@@ -0,0 +1,37 @@
+const { assert } = require('chai')
+const { expectRevert } = require('@openzeppelin/test-helpers')
+
+contract('RandomNumberConsumer', accounts => {
+    const RandomNumberConsumer = artifacts.require('RandomNumberConsumer')
+    const VRFCoordinatorMock = artifacts.require('VRFCoordinatorMock')
+    const { LinkToken } = require('@chainlink/contracts/truffle/v0.4/LinkToken')
+    const defaultAccount = accounts[0]
+    let randomNumberConsumer, vrfCoordinatorMock, seed, link, keyhash, fee
+
+    describe('#request random number', () => {
+        beforeEach(async () => {
+            keyhash = '0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4'
+            fee = '1000000000000000000'
+            seed = 123
+            link = await LinkToken.new({ from: defaultAccount })
+            vrfCoordinatorMock = await VRFCoordinatorMock.new(link.address, { from: defaultAccount })
+            randomNumberConsumer = await RandomNumberConsumer.new(link.address, keyhash, vrfCoordinatorMock.address, fee, { from: defaultAccount })
+        })
+        it('it revert without LINK', async () => {
+            await expectRevert.unspecified(
+                randomNumberConsumer.getRandomNumber(seed, { from: defaultAccount })
+            )
+        })
+        it('returns a random number with link', async () => {
+            await link.transfer(randomNumberConsumer.address, web3.utils.toWei('1', 'ether'), { from: defaultAccount })
+            let transaction = await randomNumberConsumer.getRandomNumber(seed, { from: defaultAccount })
+            assert.exists(transaction.receipt.rawLogs)
+            // This is the event that is emitted
+            let requestId = transaction.receipt.rawLogs[3].topics[0]
+            // let requestId = await randomNumberConsumer.lastRequestId({ from: defaultAccount })
+            await vrfCoordinatorMock.callBackWithRandomness(requestId, '777', randomNumberConsumer.address, { from: defaultAccount })
+            let randomNumber = await randomNumberConsumer.randomResult({ from: defaultAccount })
+            assert.equal(randomNumber, 777)
+        })
+    })
+})

truffle-config.js

@@ -1,5 +1,5 @@
 const HDWalletProvider = require('@truffle/hdwallet-provider')
-require('dotenv').config();
+require('dotenv').config()
 
 const mnemonic = process.env.MNEMONIC
 const url = process.env.RPC_URL
@@ -26,7 +26,7 @@ module.exports = {
   },
   compilers: {
     solc: {
-      version: '0.6.12',
+      version: '0.6.6',
     },
   },
 }