[TASK] Add Transaction.getBalanceChanges, computed from metadata

test/metadata-test.js

@@ -0,0 +1,178 @@
+var assert = require('assert');
+var fs = require('fs');
+var utils  = require('./testutils');
+var Meta = utils.load_module('meta').Meta;
+
+// Pay 100 XRP from rKmB to rLDY to create rLDY account
+var createAccountBalanceChanges = [
+  { address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+    balance_change: {
+      value: '100',
+      currency: 'XRP',
+      issuer: ''
+    }
+  },
+  { address: 'rKmBGxocj9Abgy25J51Mk1iqFzW9aVF9Tc',
+    balance_change: {
+      value: '-100.012',
+      currency: 'XRP',
+      issuer: ''
+    },
+  }
+];
+
+// Pay 0.01 USD from rKmB to rLDY where rLDY starts with no USD
+var usdFirstPaymentBalanceChanges = [
+  { address: 'rKmBGxocj9Abgy25J51Mk1iqFzW9aVF9Tc',
+    balance_change: {
+      value: '-0.01',
+      currency: 'USD',
+      issuer: 'rMwjYedjc7qqtKYVLiAccJSmCwih4LnE2q'
+    }
+  },
+  { address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+    balance_change: {
+      value: '0.01',
+      currency: 'USD',
+      issuer: 'rMwjYedjc7qqtKYVLiAccJSmCwih4LnE2q'
+    }
+  },
+  { address: 'rKmBGxocj9Abgy25J51Mk1iqFzW9aVF9Tc',
+    balance_change: {
+      value: '-0.012',
+      currency: 'XRP',
+      issuer: ''
+    }
+  }
+];
+
+// Pay 0.2 USD from rLDY to rKmB where rLDY starts with 0.2 USD
+var usdFullPaymentBalanceChanges = [
+  { address: 'rKmBGxocj9Abgy25J51Mk1iqFzW9aVF9Tc',
+    balance_change: {
+      value: '0.2',
+      currency: 'USD',
+      issuer: 'rMwjYedjc7qqtKYVLiAccJSmCwih4LnE2q'
+    }
+  },
+  { address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+    balance_change: {
+      value: '-0.2',
+      currency: 'USD',
+      issuer: 'rMwjYedjc7qqtKYVLiAccJSmCwih4LnE2q'
+    }
+  },
+  { address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+    balance_change: {
+      value: '-0.012',
+      currency: 'XRP',
+      issuer: ''
+    }
+  }
+];
+
+// Pay 0.01 USD from rKmB to rLDY where rLDY starts with 0.01 USD
+var usdPaymentBalanceChanges = usdFirstPaymentBalanceChanges;
+
+// Set trust limit to 200 USD on rLDY when it has a trust limit of 100 USD
+// and has a balance of 0.02 USD
+var setTrustlineBalanceChanges = [
+  {
+    address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+    balance_change: {
+      value: '-0.012',
+      currency: 'XRP',
+      issuer: ''
+    }
+  }
+];
+
+// Set trust limit to 100 USD on rLDY when it has no trustline
+var createTrustlineBalanceChanges = setTrustlineBalanceChanges;
+
+// Pay 0.02 USD from rLDY to rKmB when rLDY has a trust limit of 0
+// for USD, but still has a balance of 0.02 USD; which closes the trustline
+var deleteTrustlineBalanceChanges = [
+    {
+      address: 'rKmBGxocj9Abgy25J51Mk1iqFzW9aVF9Tc',
+      balance_change: {
+        value: '0.02',
+        currency: 'USD',
+        issuer: 'rMwjYedjc7qqtKYVLiAccJSmCwih4LnE2q'
+      }
+    },
+    {
+      address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+      balance_change: {
+        value: '-0.02',
+        currency: 'USD',
+        issuer: 'rMwjYedjc7qqtKYVLiAccJSmCwih4LnE2q'
+      }
+    },
+    {
+      address: 'rLDYrujdKUfVx28T9vRDAbyJ7G2WVXKo4K',
+      balance_change: {
+        value: '-0.012',
+        currency: 'XRP',
+        issuer: ''
+      }
+    }
+];
+
+// Set trust limit to zero on rLDY when it has a balance of 0.02 USD
+var removeTrustBalanceChanges = setTrustlineBalanceChanges;
+
+
+function loadFixture(filename) {
+  var path = __dirname + '/fixtures/' + filename;
+  return JSON.parse(fs.readFileSync(path));
+}
+
+function parseBalanceChanges(metadata) {
+  var meta = new Meta(metadata);
+  return JSON.parse(JSON.stringify(meta.parseBalanceChanges()));
+}
+
+describe('parseBalanceChanges', function() {
+  it('XRP create account', function() {
+    var paymentResponse = loadFixture('payment-xrp-create-account.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, createAccountBalanceChanges);
+  });
+  it('USD payment to account with no USD', function() {
+    var filename = 'payment-iou-destination-no-balance.json';
+    var paymentResponse = loadFixture(filename);
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, usdFirstPaymentBalanceChanges);
+  });
+  it('USD payment of all USD in source account', function() {
+    var paymentResponse = loadFixture('payment-iou-spend-full-balance.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, usdFullPaymentBalanceChanges);
+  });
+  it('USD payment to account with USD', function() {
+    var paymentResponse = loadFixture('payment-iou.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, usdPaymentBalanceChanges);
+  });
+  it('Set trust limit to 0 with balance remaining', function() {
+    var paymentResponse = loadFixture('trustline-set-limit-to-zero.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, removeTrustBalanceChanges);
+  });
+  it('Create trustline', function() {
+    var paymentResponse = loadFixture('trustline-create.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, createTrustlineBalanceChanges);
+  });
+  it('Set trustline', function() {
+    var paymentResponse = loadFixture('trustline-set-limit.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, setTrustlineBalanceChanges);
+  });
+  it('Delete trustline', function() {
+    var paymentResponse = loadFixture('trustline-delete.json');
+    var result = parseBalanceChanges(paymentResponse.metadata);
+    assert.deepEqual(result, deleteTrustlineBalanceChanges);
+  });
+});