[enb#425] update test techs/write-file - check exists file or not exi…

…sts of created with 'write-file'

test/techs/write-file.test.js

@@ -1,13 +1,19 @@
 var mockFS = require('mock-fs'),
     MockNode = require('mock-enb/lib/mock-node'),
-    FileProviderTech = require('../../techs/write-file');
+    WriteFileTech = require('../../techs/write-file');
 
 describe('techs/write-file', function () {
     var bundle,
         resolveSpy,
         rejectSpy;
 
     beforeEach(function () {
+        mockFS({
+            'bundles': mockFS.directory({
+                mode: 0755
+            })
+        });
+
         bundle = new MockNode('bundle');
         resolveSpy = sinon.spy(bundle, 'resolveTarget');
         rejectSpy = sinon.spy(bundle, 'rejectTarget');
@@ -18,7 +24,14 @@ describe('techs/write-file', function () {
     });
 
     it('should write target file to file system', function () {
-
+        return bundle.runTech(WriteFileTech, {
+                target: '?.txt',
+                content: 'I\'m here'
+            })
+            .should.be.fulfilled
+            .then(function () {
+                mockFS.statSync('bundles/bunlde/bundle.txt').isFile().should.be.ok;
+                resolveSpy.should.calledWith('bundle.txt');
+            });
     });
-
 });