[New] bin/tape: add --strict

When --strict is passed and zero files are found, tape will exit nonzero

bin/tape

@@ -9,8 +9,8 @@ var objectKeys = require('object-keys');
 var opts = parseOpts(process.argv.slice(2), {
 	alias: { r: 'require', i: 'ignore' },
 	string: ['require', 'ignore', 'ignore-pattern'],
-	boolean: ['only'],
-	default: { r: [], i: null, 'ignore-pattern': null, only: null }
+	boolean: ['only', 'strict'],
+	default: { r: [], i: null, 'ignore-pattern': null, only: null, strict: false }
 });
 
 if (typeof opts.only === 'boolean') {
@@ -91,6 +91,11 @@ var files = opts._.reduce(function (result, arg) {
 	return requireResolve(resolvePath(cwd, file));
 });
 
+if (opts.strict && files.length === 0) {
+	console.error('No test files found!');
+	process.exit(127);
+}
+
 var hasImport = require('has-dynamic-import');
 
 var tape = require('../');

readme.markdown

@@ -68,6 +68,12 @@ $ tape 'tests/**/*.js'
 $ tape "tests/**/*.js"
 ```
 
+If you want `tape` to error when no files are found, pass `--strict`:
+
+```sh
+$ tape --strict 'tests/**/*.js'
+```
+
 ## Preloading modules
 
 Additionally, it is possible to make `tape` load one or more modules before running any tests, by using the `-r` or `--require` flag. Here's an example that loads [babel-register](https://babeljs.io/docs/usage/require/) before running any tests, to allow for JIT compilation:

test/strict.js

@@ -0,0 +1,75 @@
+'use strict';
+
+var tap = require('tap');
+var path = require('path');
+var exec = require('child_process').exec;
+
+var stripFullStack = require('./common').stripFullStack;
+var stripDeprecations = require('./common').stripDeprecations;
+
+var tapeBin = 'node ' + path.join(__dirname, '../bin/tape');
+
+var expectedStackTraceBug = (/^3\.[012]\.\d+$/).test(process.versions.node); // https://github.com/nodejs/node/issues/2581
+var expectedExitCodeOnError = (/^0\.(?:9|10)/).test(process.versions.node) ? 8 : 127; // node v0.9 sets this exit code to 8, for some reason
+
+tap.test(
+	'should throw error when --strict is passed via cli and no files are found',
+	{ todo: expectedStackTraceBug ? 'Fails on these node versions' : false },
+	function (tt) {
+		tt.plan(3);
+
+		exec(tapeBin + ' --strict "no*files*found"', { cwd: path.join(__dirname) }, function (err, stdout, stderr) {
+			tt.same(stdout.toString('utf8'), '');
+			tt.match(stripFullStack(stderr.toString('utf8')).join('\n'), /^No test files found!\n$/);
+			tt.equal(err.code, 127);
+		});
+	}
+);
+
+tap.test(
+	'should not throw error when --no-strict is passed via cli and no files are found',
+	{ todo: expectedStackTraceBug ? 'Fails on these node versions' : false },
+	function (tt) {
+		tt.plan(3);
+
+		exec(tapeBin + ' --no-strict "no*files*found"', { cwd: path.join(__dirname) }, function (err, stdout, stderr) {
+			tt.equal(stripDeprecations(stderr.toString('utf8')), '');
+			tt.same(stripFullStack(stdout.toString('utf8')), [
+				'TAP version 13',
+				'',
+				'1..0',
+				'# tests 0',
+				'# pass  0',
+				'',
+				'# ok',
+				'',
+				''
+			]);
+			tt.equal(err, null); // code 0
+		});
+	}
+);
+
+tap.test(
+	'should not throw error when no files are found',
+	{ todo: expectedStackTraceBug ? 'Fails on these node versions' : false },
+	function (tt) {
+		tt.plan(3);
+
+		exec(tapeBin + ' "no*files*found"', { cwd: path.join(__dirname) }, function (err, stdout, stderr) {
+			tt.equal(stripDeprecations(stderr.toString('utf8')), '');
+			tt.same(stripFullStack(stdout.toString('utf8')), [
+				'TAP version 13',
+				'',
+				'1..0',
+				'# tests 0',
+				'# pass  0',
+				'',
+				'# ok',
+				'',
+				''
+			]);
+			tt.equal(err, null); // code 0
+		});
+	}
+);