refactor: convert samples test from ava to mocha

samples/package.json

@@ -9,8 +9,7 @@
     "node": ">=8"
   },
   "scripts": {
-    "system-test": "ava -T 1m --verbose system-test/*.test.js",
-    "test": "npm run system-test"
+    "test": "mocha system-test/*.js --timeout 600000"
   },
   "dependencies": {
     "@google-cloud/logging-bunyan": "^0.9.4",

samples/system-test/.eslintrc.yml

@@ -1,4 +1,6 @@
 ---
+env:
+  mocha: true
 rules:
   node/no-unpublished-require: off
   node/no-unsupported-features: off

samples/system-test/express.test.js

@@ -16,22 +16,19 @@
 'use strict';
 
 const path = require(`path`);
-const test = require(`ava`);
+const assert = require(`assert`);
 const tools = require(`@google-cloud/nodejs-repo-tools`);
 const execa = require(`execa`);
 const delay = require(`delay`);
 const {Logging} = require('@google-cloud/logging');
 const logging = new Logging();
 const got = require('got');
 
+before(tools.checkCredentials);
 const lb = require('@google-cloud/logging-bunyan');
 const {APP_LOG_SUFFIX} = lb.express;
 
-test.before(tools.checkCredentials);
-
-test.serial(`should write using bunyan`, async t => {
-  t.plan(4);
-
+it(`should write using bunyan`, async () => {
   // Start the express server.
   execa(process.execPath, ['express.js'], {
     cwd: path.join(__dirname, `..`),
@@ -50,9 +47,9 @@ test.serial(`should write using bunyan`, async t => {
   // Make sure the log was written to Stackdriver Logging.
   const log = logging.log(`samples_express_${APP_LOG_SUFFIX}`);
   const entries = (await log.getEntries({pageSize: 1}))[0];
-  t.is(entries.length, 1);
+  assert.strictEqual(entries.length, 1);
   const entry = entries[0];
-  t.is('this is an info log message', entry.data.message);
-  t.truthy(entry.metadata.trace, 'should have a trace property');
-  t.truthy(entry.metadata.trace.match(/projects\/.*\/traces\/.*/));
+  assert.strictEqual('this is an info log message', entry.data.message);
+  assert.ok(entry.metadata.trace, 'should have a trace property');
+  assert.ok(entry.metadata.trace.match(/projects\/.*\/traces\/.*/));
 });

samples/system-test/quickstart.test.js

@@ -16,15 +16,15 @@
 'use strict';
 
 const path = require(`path`);
-const test = require(`ava`);
+const assert = require(`assert`);
 const tools = require(`@google-cloud/nodejs-repo-tools`);
 
-test.before(tools.checkCredentials);
+before(tools.checkCredentials);
 
-test.serial(`should write using bunyan`, async t => {
+it(`should write using bunyan`, async () => {
   const output = await tools.runAsync(
     `node quickstart.js`,
     path.join(__dirname, `..`)
   );
-  t.is(output.includes('99%'), true);
+  assert.strictEqual(output.includes('99%'), true);
 });