Expose the createCwd and createTmp options

lib/index.js

@@ -71,9 +71,14 @@ function setProcess(cwd, chdir) {
 /**
  * Swap out the fs bindings for a mock file system.
  * @param {Object} config Mock file system configuration.
+ * @param {Object} options Any filesystem options.
+ * @param {boolean} options.createCwd Create a directory for `process.cwd()`
+ *     (defaults to `true`).
+ * @param {boolean} options.createTmp Create a directory for `os.tmpdir()`
+ *     (defaults to `true`).
  */
-var exports = module.exports = function mock(config) {
-  var system = FileSystem.create(config);
+var exports = module.exports = function mock(config, options) {
+  var system = FileSystem.create(config, options);
   var binding = new Binding(system);
   setBinding(binding, binding.Stats);
 
@@ -104,10 +109,15 @@ exports.restore = function() {
 /**
  * Create a mock fs module based on the given file system configuration.
  * @param {Object} config File system configuration.
+ * @param {Object} options Any filesystem options.
+ * @param {boolean} options.createCwd Create a directory for `process.cwd()`
+ *     (defaults to `true`).
+ * @param {boolean} options.createTmp Create a directory for `os.tmpdir()`
+ *     (defaults to `true`).
  * @return {Object} A fs module with a mock file system.
  */
-exports.fs = function(config) {
-  var system = FileSystem.create(config);
+exports.fs = function(config, options) {
+  var system = FileSystem.create(config, options);
   var binding = new Binding(system);
 
   // inject the mock binding

test/lib/index.spec.js

@@ -22,10 +22,6 @@ describe('The API', function() {
       mock.restore();
     });
 
-  });
-
-  describe('mock()', function() {
-
     it('creates process.cwd() and os.tmpdir() by default', function() {
       mock();
 
@@ -43,6 +39,30 @@ describe('The API', function() {
       mock.restore();
     });
 
+    it('passes the createCwd option to the FileSystem constructor', function() {
+      mock({}, {createCwd: false});
+
+      assert.isFalse(fs.existsSync(process.cwd()));
+
+      mock.restore();
+    });
+
+    it('passes the createTmp option to the FileSystem constructor', function() {
+      mock({}, {createTmp: false});
+
+      var tmp;
+      if (os.tmpdir) {
+        tmp = os.tmpdir();
+      } else if (os.tmpDir) {
+        tmp = os.tmpDir();
+      }
+      if (tmp) {
+        assert.isFalse(fs.existsSync(tmp));
+      }
+
+      mock.restore();
+    });
+
   });
 
   describe('mock.restore()', function() {
@@ -179,6 +199,20 @@ describe('The API', function() {
 
     });
 
+    it('passes options to the FileSystem constructor', function() {
+
+      var mockFs = mock.fs({
+        '/path/to/file.txt': 'file content'
+      }, {
+        createCwd: false,
+        createTmp: false
+      });
+
+      assert.isTrue(mockFs.existsSync('/path/to/file.txt'));
+      assert.deepEqual(mockFs.readdirSync('/'), ['path']);
+
+    });
+
     it('accepts an arbitrary nesting of files and directories', function() {
 
       var mockFs = mock.fs({