diff --git a/A3_3_Testing_with_Regtest.md b/A3_3_Testing_with_Regtest.md
deleted file mode 100644
index 8d22e1c..0000000
--- a/A3_3_Testing_with_Regtest.md
+++ /dev/null
@@ -1,138 +0,0 @@
-# A3.3: Testing with Regtest
-
-> **NOTE:** This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.
-
-This document explains how to test transactions and situations using regtest (regression test).
-
-## Verifying balance
-
-After [mining blocks](A3_2_Mining_with_Regtest.md) and getting the rewards, you can verify the balance on your wallet:
-```
-$ bitcoin-cli -regtest getbalance
-50.00000000
-```
-
-## Validating the Regtest
-Now you should be able to use this balance for any type of interaction with the private Blockchain, such as sending Bitcoin transactions according to [Chapter 4]((04_0_Sending_Bitcoin_Transactions.md)). The only difference is that you need to use the flag `-regtest` when running the `bitcoin-cli` in order for the request to be sent to the Regtest Bitcoin daemon.
-
-It is important to note that for your transactions to complete, you will have to generate (mine) new blocks, so that the transactions can be included.
-
-For example, to create a transaction and include into a block, you should use the `sendtoaddress` command:
-```
-$ bitcoin-cli -regtest sendtoaddress [address] 15.1
-e834a4ac6ef754164c8e3f0be4f34531b74b768199ffb244ab9f6cb1bbc7465a
-```
-
-The output is the transaction hash included in the blockchain. You can verify the details using the `gettransaction`:
-```
-$ bitcoin-cli -regtest gettransaction e834a4ac6ef754164c8e3f0be4f34531b74b768199ffb244ab9f6cb1bbc7465a
-{
-  "amount": 0.00000000,
-  "fee": -0.00178800,
-  "confirmations": 0,
-  "trusted": false,
-  "txid": "e834a4ac6ef754164c8e3f0be4f34531b74b768199ffb244ab9f6cb1bbc7465a",
-  "walletconflicts": [
-  ],
-  "time": 1513204730,
-  "timereceived": 1513204730,
-  "bip125-replaceable": "unknown",
-  "details": [
-    {
-      "account": "",
-      "address": "mjtN3C97kuWMgeBbxdB7hG1bjz24Grx2vA",
-      "category": "send",
-      "amount": -15.10000000,
-      "label": "",
-      "vout": 1,
-      "fee": -0.00178800,
-      "abandoned": false
-    },
-    {
-      "account": "",
-      "address": "mjtN3C97kuWMgeBbxdB7hG1bjz24Grx2vA",
-      "category": "receive",
-      "amount": 15.10000000,
-      "label": "",
-      "vout": 1
-    }
-  ],
-  "hex": "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"
-}
-```
-
-After creating a transaction, it has to be confirmed and recorded in a block on the blockchain.
-Most applications require a six-block confirmations to consider the transaction as irreversible. If that is your case, you can mine additional 6 blocks into your Regtest chain:
-```
-$ bitcoin-cli -regtest generate 6
-[
-  "33549b2aa249f0a814db4a2ba102194881c14a2ac041c23dcc463b9e4e128e9f",
-  "2cc5c2012e2cacf118f9db4cdd79582735257f0ec564418867d6821edb55715e",
-  "128aaa99e7149a520080d90fa989c62caeda11b7d06ed1965e3fa7c76fa1d407",
-  "6037cc562d97eb3984cca50d8c37c7c19bae8d79b8232b92bec6dcc9708104d3",
-  "2cb276f5ed251bf629dd52fd108163703473f57c24eac94e169514ce04899581",
-  "57193ba8fd2761abf4a5ebcb4ed1a9ec2e873d67485a7cb41e75e13c65928bf3"
-]
-```
-
-
-## Testing with NodeJS
-
-When you are on regtest, you are able to simulate edge cases and attacks that might happen in the real world, such  as double spend.
-
-As discussed elsewhere in this course, using software libraries might give you more sophisticated access to some RPC commands. In this case, [bitcointest by dgarage](https://github.com/dgarage/bitcointest) for NodeJS can be used to simulate a transaction from one wallet to another; you can check [their guide](https://www.npmjs.com/package/bitcointest) for more specific attack simulations, such as Double Spend.
-
-See [§17.3](17_3_Accessing_Bitcoind_with_NodeJS.md) for the most up-to-date info on install NodeJS, then add `bitcointest`:
-```
-$ npm install -g bitcointest
-```
-
-After installing `bitcointest`, you can create a `test.js` file with the following content:
-```javascript
-file: test.js
-
-const { BitcoinNet, BitcoinGraph } = require('bitcointest');
-const net = new BitcoinNet('/usr/local/bin', '/tmp/bitcointest/', 22001, 22002);
-const graph = new BitcoinGraph(net);
-
-try {
-
-  console.log('Launching nodes...');
-  
-  const nodes = net.launchBatchS(4);
-  const [ n1, n2 ] = nodes;
-  net.waitForNodesS(nodes, 20000);
-
-  console.log('Connected!');
-  const blocks = n1.generateBlocksS(110);
-  console.info('Generated 110 blocks');
-
-  console.log(`n2.balance (before) = ${n2.getBalanceS()}`);
-
-  const sometxid = n1.sendToNodeS(n2, 100);
-  console.log(`Generated transaction = ${sometxid}`);
-  n1.generateBlocksS(110);
-  n2.waitForBalanceChangeS(0);
-
-  const sometx = n2.getTransactionS(sometxid);
-  console.log(`n2.balance (after) = ${n2.getBalanceS()}`);
-
-
-} catch (e) {
-  console.error(e);
-  net.shutdownS();
-  throw e;
-}
-```
-
-As shown, this will generate blocks and a transaction:
-```
-$ node test.js
-Launching nodes...
-Connected!
-Generated 110 blocks
-n2.balance (before) = 0
-Generated transaction = 91e0040c26fc18312efb80bad6ec3b00202a83465872ecf495c392a0b6afce35
-n2.after (before) = 100
-
-```