test refactors, test multi-os on travis

Also includes various workarounds to make tests work on windows
travis.

.eslintrc

@@ -1,2 +1,6 @@
 root: true
 extends: eslint-config-silverwind
+
+# workaround for window travis
+rules:
+  linebreak-style: [0]

.travis.yml

@@ -1,4 +1,8 @@
 language: node_js
 node_js:
-  - node
-  - lts/*
+  - 8
+  - 10
+os:
+  - linux
+  - osx
+  - windows

package.json

@@ -6,7 +6,7 @@
   "repository": "silverwind/default-gateway",
   "license": "BSD-2-Clause",
   "scripts": {
-    "test": "make test"
+    "test": "eslint *.js && node --pending-deprecation --trace-deprecation --throw-deprecation --trace-warnings test.js"
   },
   "engines": {
     "node": ">=6"

test.js

@@ -1,30 +1,25 @@
 "use strict";
 
-// travis VMs don't have IPs on their interfaces
-// https://docs.travis-ci.com/user/ci-environment/#Networking
-if (process.env.CI) return;
+// IPv6 tests are skipped because Travis VMs do not support IPv6
 
 const assert = require("assert");
 const net = require("net");
 const defaultGateway = require(".");
 
-Promise.all([
-  defaultGateway.v4(),
-  defaultGateway.v6(),
-]).then(results => {
-  assert(net.isIPv4(results[0].gateway));
-  assert(net.isIPv6(results[1].gateway));
-}).catch(err => {
-  console.error(err.stack);
-  process.exit(1);
-});
+(async () => {
+  const async4 = await defaultGateway.v4();
+  assert(net.isIPv4((async4).gateway));
 
-if (defaultGateway.v4.sync) {
-  const result = defaultGateway.v4.sync();
-  assert(net.isIPv4(result.gateway));
-}
+  if (!process.env.CI) {
+    const async6 = await defaultGateway.v6();
+    assert(net.isIPv6(async6.gateway));
+  }
 
-if (defaultGateway.v6.sync) {
-  const result = defaultGateway.v6.sync();
-  assert(net.isIPv6(result.gateway));
-}
+  const sync4 = defaultGateway.v4.sync();
+  assert(net.isIPv4(sync4.gateway));
+
+  if (!process.env.CI) {
+    const sync6 = defaultGateway.v6.sync();
+    assert(net.isIPv6(sync6.gateway));
+  }
+})();