Start a basic functional test framework.

We use a standard TAP functional test format with `tNNN*.js` test
scripts under a `t/` subdirectory. These can be run directly from
the project root with `node t/t001.js` or similar, and later the
build system will be extended to find and run tests automatically.

The `t/tlib.js` file is a library of handy support functions for
this, including bringing it various test tools (tape, tape-spawn,
etc.) and functions to read in data files that store expected output
and whatnot. tlib itself is tested with `t/t001-tlib.js`.

The first test of the non-test-framework code is `t010-version.js`,
which proves we can run the `gapps` binary.

package.json

@@ -51,6 +51,7 @@
     "gulp": "^3.9.0",
     "gulp-exclude-gitignore": "^1.0.0",
     "gulp-tape": "0.0.7",
-    "tape": "^4.4.0"
+    "tape": "^4.4.0",
+    "tape-spawn": "^1.4.0"
   }
 }

t/t001-tlib.js

@@ -0,0 +1,8 @@
+'use strict'
+const tlib = require('./tlib')(module)
+
+tlib.test('readTestData', (t) => {
+    t.equal('A file containing expected output.\n',
+        tlib.readTestData(tlib.testData('expected')))
+    t.end()
+})

t/t001/expected

@@ -0,0 +1 @@
+A file containing expected output.

t/t010-version.js

@@ -0,0 +1,12 @@
+'use strict'
+const tlib = require('./tlib')(module)
+
+// Smoke test for the command line program.
+tlib.test('version', (t) => {
+    const
+        expected = require('../package.json').version + '\n',
+        cmd = tlib.spawn(t, './bin/gapps -V')
+    cmd.succeeds()
+    cmd.stdout.match(expected)
+    cmd.end()
+})

t/tlib.js

@@ -0,0 +1,22 @@
+const
+    fs          = require('fs'),
+    path        = require('path'),
+    _           = require('lodash')
+
+function testData(test_module, p) {
+    const
+        dir = path.dirname(test_module.filename),
+        subdir = path.basename(test_module.filename, '.js').split('-')[0]
+    return path.join(dir, subdir, p)
+}
+
+function readTestData(p) {
+    return fs.readFileSync(p, { encoding: 'UTF-8' })
+}
+
+module.exports = (test_module) => { return {
+    test:               require('tape'),
+    spawn:              require('tape-spawn'),
+    testData:           _.partial(testData, test_module),
+    readTestData:       readTestData,
+}}