Added totalPayments uint on PullPayments contract

test/PullPayment.js

@@ -12,7 +12,9 @@ contract('PullPayment', function(accounts) {
     let ppce = await PullPaymentMock.new();
     let callSend = await ppce.callSend(accounts[0], AMOUNT);
     let paymentsToAccount0 = await ppce.payments(accounts[0]);
+    let totalPayments = await ppce.totalPayments();
 
+    assert.equal(totalPayments, AMOUNT);
     assert.equal(paymentsToAccount0, AMOUNT);
   });
 
@@ -21,7 +23,9 @@ contract('PullPayment', function(accounts) {
     let call1 = await ppce.callSend(accounts[0], 200);
     let call2 = await ppce.callSend(accounts[0], 300);
     let paymentsToAccount0 = await ppce.payments(accounts[0]);
+    let totalPayments = await ppce.totalPayments();
 
+    assert.equal(totalPayments, 500);
     assert.equal(paymentsToAccount0, 500);
   });
 
@@ -35,6 +39,9 @@ contract('PullPayment', function(accounts) {
 
     let paymentsToAccount1 = await ppce.payments(accounts[1]);
     assert.equal(paymentsToAccount1, 300);
+
+    let totalPayments = await ppce.totalPayments();
+    assert.equal(totalPayments, 500);
   });
 
   it("can withdraw payment", async function() {
@@ -48,10 +55,16 @@ contract('PullPayment', function(accounts) {
     let payment1 = await ppce.payments(payee);
     assert.equal(payment1, AMOUNT);
 
+    let totalPayments = await ppce.totalPayments();
+    assert.equal(totalPayments, AMOUNT);
+
     let withdraw = await ppce.withdrawPayments({from: payee});
     let payment2 = await ppce.payments(payee);
     assert.equal(payment2, 0);
 
+    totalPayments = await ppce.totalPayments();
+    assert.equal(totalPayments, 0);
+
     let balance = web3.eth.getBalance(payee);
     assert(Math.abs(balance-initialBalance-AMOUNT) < 1e16);
   });