From a3308d229765ef6e7305ce5c7752d1a41e2d008d Mon Sep 17 00:00:00 2001
From: James Talmage <james@talmage.io>
Date: Fri, 13 Nov 2015 12:14:28 -0500
Subject: [PATCH]  Handle empty results from test files. Fix #198

---
 index.js                         |  1 +
 lib/babel.js                     | 15 +++++++++++++++
 lib/fork.js                      | 13 ++++++++++++-
 test/fixture/empty.js            |  8 ++++++++
 test/fixture/immediate-0-exit.js |  1 +
 test/fixture/no-tests.js         |  1 +
 test/test.js                     | 30 ++++++++++++++++++++++++++++++
 7 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 test/fixture/empty.js
 create mode 100644 test/fixture/immediate-0-exit.js
 create mode 100644 test/fixture/no-tests.js

diff --git a/index.js b/index.js
index fa1e4e000..29469f6fd 100644
--- a/index.js
+++ b/index.js
@@ -1,4 +1,5 @@
 'use strict';
+require('./lib/babel').avaRequired();
 var setImmediate = require('set-immediate-shim');
 var hasFlag = require('has-flag');
 var chalk = require('chalk');
diff --git a/lib/babel.js b/lib/babel.js
index 8f78dd45c..78957dae3 100644
--- a/lib/babel.js
+++ b/lib/babel.js
@@ -24,11 +24,26 @@ var options = {
 	]
 };
 
+var avaRequired;
+
+module.exports = {
+	avaRequired: function () {
+		avaRequired = true;
+	}
+};
+
 var transpiled = babel.transformFileSync(testPath, options);
 requireFromString(transpiled.code, testPath, {
 	appendPaths: module.paths
 });
 
+if (!avaRequired) {
+	console.error('No tests found in ' + testPath + ', make sure to import "ava" at the top of your test file');
+	setImmediate(function () {
+		process.exit(1);
+	});
+}
+
 process.on('message', function (message) {
 	if (message['ava-kill-command']) {
 		process.exit(0);
diff --git a/lib/fork.js b/lib/fork.js
index 379650203..8700b86a3 100644
--- a/lib/fork.js
+++ b/lib/fork.js
@@ -34,8 +34,19 @@ module.exports = function (args) {
 		ps.on('exit', function (code) {
 			if (code > 0 && code !== 143) {
 				reject(new Error(file + ' exited with a non-zero exit code: ' + code));
-			} else {
+			} else if (testResults) {
+				if (!testResults.tests.length) {
+					testResults.stats.failCount++;
+					testResults.tests.push({
+						duration: 0,
+						title: file,
+						error: new Error('No tests for ' + file),
+						type: 'test'
+					});
+				}
 				resolve(testResults);
+			} else {
+				reject(new Error('Never got test results from: ' + file));
 			}
 		});
 	});
diff --git a/test/fixture/empty.js b/test/fixture/empty.js
new file mode 100644
index 000000000..03d715446
--- /dev/null
+++ b/test/fixture/empty.js
@@ -0,0 +1,8 @@
+/*
+                         __
+    ____   _____ _______/  |_ ___.__.
+  _/ __ \ /     \\____ \   __<   |  |
+  \  ___/|  Y Y  \  |_> >  |  \___  |
+   \___  >__|_|  /   __/|__|  / ____|
+       \/      \/|__|         \/
+ */
diff --git a/test/fixture/immediate-0-exit.js b/test/fixture/immediate-0-exit.js
new file mode 100644
index 000000000..dcbbff6c9
--- /dev/null
+++ b/test/fixture/immediate-0-exit.js
@@ -0,0 +1 @@
+process.exit(0);
diff --git a/test/fixture/no-tests.js b/test/fixture/no-tests.js
new file mode 100644
index 000000000..5be323f69
--- /dev/null
+++ b/test/fixture/no-tests.js
@@ -0,0 +1 @@
+import test from '../../';
diff --git a/test/test.js b/test/test.js
index 2a7dee4d2..0491540f5 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1087,3 +1087,33 @@ test('titles of both passing and failing tests and AssertionErrors are displayed
 		t.end();
 	});
 });
+
+test('empty test files creates a failure with a helpful warning', function (t) {
+	t.plan(2);
+
+	execCli('fixture/empty.js', function (err, stdout) {
+		t.ok(err);
+		t.ok(/No tests found.*?import "ava"/.test(stdout));
+		t.end();
+	});
+});
+
+test('test file with no tests creates a failure with a helpful warning', function (t) {
+	t.plan(2);
+
+	execCli('fixture/no-tests.js', function (err, stdout, stderr) {
+		t.ok(err);
+		t.ok(/No tests/.test(stderr));
+		t.end();
+	});
+});
+
+test('test file that immediately exits with 0 exit code ', function (t) {
+	t.plan(2);
+
+	execCli('fixture/immediate-0-exit.js', function (err, stdout, stderr) {
+		t.ok(err);
+		t.ok(/Never got test results/.test(stderr));
+		t.end();
+	});
+});