Added test freeLogs

Author: Agustin Aguilar

tests/api/freeLogs.js

@@ -0,0 +1,52 @@
+const tape = require('tape')
+const VM = require('../../lib/index')
+
+/*
+contract Contract1 {
+    event Event();
+    function() external {
+        emit Event();
+    }
+}
+*/
+
+const code = Buffer.from('6080604052348015600f57600080fd5b506040517f57050ab73f6b9ebdd9f76b8d4997793f48cf956e965ee070551b9ca0bb71584e90600090a10000a165627a7a72305820f80265dc41ca5376abe548a02070b68b91119b77dc54c76563b9c19a758cf26f0029', 'hex')
+
+tape('VM with free logs', async (t) => {
+  t.test('should run code without charging for log opcode', async (st) => {
+    const vm = new VM({ emitFreeLogs: true })
+    vm.runCode({
+      code: code,
+      gasLimit: 810
+    }, function (err, val) {
+      st.notOk(err)
+      st.ok(val.runState.gasLeft >= 0x177, 'should expend less gas')
+      st.ok(val.logs.length === 1, 'should emit event')
+      st.end()
+    })
+  })
+  t.test('should emit event on static context', async (st) => {
+    const vm = new VM({ emitFreeLogs: true })
+    vm.runCode({
+      code: code,
+      gasLimit: 24000,
+      static: true
+    }, function (err, val) {
+      st.notOk(err)
+      st.ok(val.logs.length === 1, 'should emit event')
+      st.end()
+    })
+  })
+  t.test('should not emit event on static context if flag is not set', async (st) => {
+    const vm = new VM()
+    vm.runCode({
+      code: code,
+      gasLimit: 24000,
+      static: true
+    }, function (err, val) {
+      st.ok(err)
+      st.ok(val.logs.length === 0, 'should emit zero events')
+      st.end()
+    })
+  })
+})