Mock interfaces has isSubscription flag (#64)

* Mock interfaces has isSubscription flag

* chain_newHead mock

packages/api-jsonrpc/src/extra/getBlockNumber.js

@@ -13,6 +13,7 @@ import type { InterfaceMethodDefinition } from '../types';
     Returns the best blockNumber available on the client
 */
 module.exports = ({
+  isSubscription: true,
   inputs: [],
   output: { type: 'BlockNumber' }
 }: InterfaceMethodDefinition);

packages/api-jsonrpc/src/extra/getClientTime.js

@@ -13,6 +13,7 @@ import type { InterfaceMethodDefinition } from '../types';
     Returns the current time on the running node
 */
 module.exports = ({
+  isSubscription: true,
   inputs: [],
   output: { type: 'U64' }
 }: InterfaceMethodDefinition);

packages/api-provider/src/mock/mocks.js

@@ -5,8 +5,27 @@
 
 import type { MockState, MockState$Subscription$Callback } from './types';
 
+const bnToU8a = require('@polkadot/util/bn/toU8a');
+const randomAsHex = require('@polkadot/util-crypto/random/asHex');
+
+function makeBlockHeader (prevNumber: number) {
+  const blockNumber = prevNumber++;
+
+  return {
+    digest: {
+      logs: []
+    },
+    extrinsicsRoot: randomAsHex(),
+    number: blockNumber,
+    parentHash: prevNumber === -1
+      ? '0x0000000000000000000000000000000000000000000000000000000000000000'
+      : bnToU8a(prevNumber, 256),
+    stateRoot: bnToU8a(blockNumber, 256)
+  };
+}
+
 module.exports = function mocks ({ subscriptions }: MockState): void {
-  let blockNumber = 0;
+  let newHead = makeBlockHeader(-1);
 
   const updateSubs = (method, value) => {
     subscriptions[method].lastValue = value;
@@ -24,7 +43,10 @@ module.exports = function mocks ({ subscriptions }: MockState): void {
   };
 
   setInterval(() => {
-    updateSubs('extra_getBlockNumber', `0x${(++blockNumber).toString(16)}`);
+    newHead = makeBlockHeader(newHead.number);
+
+    updateSubs('extra_getBlockNumber', `0x${(newHead.number).toString(16)}`);
+    updateSubs('chain_newHead', newHead);
   }, 5000);
 
   setInterval(() => {

packages/api-provider/src/mock/state.js

@@ -12,6 +12,7 @@ const METHODS = Array.prototype.concat.apply(
   [], Object.keys(interfaces).map((section) => {
     return Object
       .keys(interfaces[section].methods)
+      .filter((method) => interfaces[section].methods[method].isSubscription)
       .map((method) => `${section}_${method}`);
   })
 );