This implements -r and --require as command line options

@Raynos accurately pointed out that the source map support was a
bit too specific, and felt outside of the purview of tape.
As a more general solution, this implements the `-r` and `--require`
CLI flags, which will allow a user to load node modules before any
tests are run. For example, if someon wants to enable source map
support in node, they might do:

    tape -r source-map-support/register test/*.js

bin/tape

@@ -1,12 +1,32 @@
 #!/usr/bin/env node
 
-var path = require('path');
+var resolveModule = require('resolve').sync;
+var resolvePath = require('path').resolve;
+var parseOpts = require('minimist');
 var glob = require('glob');
 
-process.argv.slice(2).forEach(function (arg) {
+var opts = parseOpts(process.argv.slice(2), {
+        alias: { 'r': 'require' },
+        string: 'require',
+        default: {'r': [] }
+    });
+
+var cwd = process.cwd();
+
+/* If only one require is specified, the value of `opts.require`
+ * will be a string. This is why we concatenate.
+ */
+;[].concat(opts.require).forEach(function(module) {
+    /* The `module &&` ensures we ignore `-r ""`, trailing `-r` or other
+     * silly things the user might (inadvertedly) be doing.
+     */
+    module && require(resolveModule(module, { basedir: cwd }));
+});
+
+opts._.forEach(function (arg) {
     glob(arg, function (err, files) {
         files.forEach(function (file) {
-            require(path.resolve(process.cwd(), file));
+            require(resolvePath(cwd, file));
         });
     });
 });

package.json

@@ -15,7 +15,9 @@
     "glob": "~5.0.3",
     "has": "~1.0.1",
     "inherits": "~2.0.1",
+    "minimist": "1.2.0",
     "object-inspect": "~1.0.0",
+    "resolve": "1.1.6",
     "resumer": "~0.0.0",
     "string.prototype.trim": "^1.1.1",
     "through": "~2.3.4"

test/require.js

@@ -0,0 +1,83 @@
+var tap = require('tap');
+var spawn = require('child_process').spawn;
+var trim = require('string.prototype.trim');
+
+tap.test('requiring a single module', function (t) {
+    t.plan(2);
+
+    var tc = tap.createConsumer();
+
+    var rows = [];
+    tc.on('data', function (r) { rows.push(r) });
+    tc.on('end', function () {
+        var rs = rows.map(function (r) {
+            if (r && typeof r === 'object') {
+                return { id : r.id, ok : r.ok, name : trim(r.name) };
+            }
+            else return r;
+        });
+        t.same(rs, [
+            'TAP version 13',
+            'module-a',
+            { id: 1, ok: true, name: 'loaded module a' },
+            'test-a',
+            { id: 2, ok: true, name: 'module-a loaded in same context'},
+            { id: 3, ok: true, name: 'test ran after module-a was loaded'},
+            'tests 3',
+            'pass  3',
+            'ok'
+        ]);
+    });
+
+    var ps = tape('-r ./require/a require/test-a.js');
+    ps.stdout.pipe(tc);
+    ps.on('exit', function (code) {
+        t.equal(code, 0);
+    });
+});
+
+tap.test('requiring multiple modules', function (t) {
+    t.plan(2);
+
+    var tc = tap.createConsumer();
+
+    var rows = [];
+    tc.on('data', function (r) { rows.push(r) });
+    tc.on('end', function () {
+        var rs = rows.map(function (r) {
+            if (r && typeof r === 'object') {
+                return { id : r.id, ok : r.ok, name : trim(r.name) };
+            }
+            else return r;
+        });
+        t.same(rs, [
+            'TAP version 13',
+            'module-a',
+            { id: 1, ok: true, name: 'loaded module a' },
+            'module-b',
+            { id: 2, ok: true, name: 'loaded module b' },
+            'test-a',
+            { id: 3, ok: true, name: 'module-a loaded in same context'},
+            { id: 4, ok: true, name: 'test ran after module-a was loaded'},
+            'test-b',
+            { id: 5, ok: true, name: 'module-b loaded in same context'},
+            { id: 6, ok: true, name: 'test ran after module-b was loaded'},
+            'tests 6',
+            'pass  6',
+            'ok'
+        ]);
+    });
+
+    var ps = tape('-r ./require/a -r ./require/b require/test-a.js require/test-b.js');
+    ps.stdout.pipe(tc);
+    ps.on('exit', function (code) {
+        t.equal(code, 0);
+    });
+});
+
+function tape(args) {
+  var proc = require('child_process')
+  var bin = __dirname + '/../bin/tape'
+
+  return proc.spawn(bin, args.split(' '), { cwd: __dirname })
+}

test/require/a.js

@@ -0,0 +1,8 @@
+var tape = require('../..');
+
+tape.test('module-a', function(t) {
+  t.pass('loaded module a')
+  t.end()
+})
+
+global.module_a = true

test/require/b.js

@@ -0,0 +1,8 @@
+var tape = require('../..');
+
+tape.test('module-b', function(t) {
+  t.pass('loaded module b')
+  t.end()
+})
+
+global.module_b = true

test/require/test-a.js

@@ -0,0 +1,7 @@
+var tape = require('../..');
+
+tape.test('test-a', function(t) {
+  t.ok(global.module_a, 'module-a loaded in same context')
+  t.pass('test ran after module-a was loaded')
+  t.end()
+})

test/require/test-b.js

@@ -0,0 +1,7 @@
+var tape = require('../..');
+
+tape.test('test-b', function(t) {
+  t.ok(global.module_b, 'module-b loaded in same context')
+  t.pass('test ran after module-b was loaded')
+  t.end()
+})