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POGroovy mocking File constructor, verify write on newly created files
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  1. POGroovy mocking File constructor, verify write on newly created files
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    copied!<p>Im trying to mock a new File generated in a loop. Simplified example:</p> <pre><code>class FileClass { def basePath def listObjects = [] def createFilePerObject() { listObjects.each {currentObject -&gt; File currentFile = new File("${basePath.toString()}/${currentObject.objectName}") currentFile.write currentObject.objectContent //Verify this behaviour!! } } } class SimpleObject { String objectName String objectContent } </code></pre> <p>And, the test:</p> <pre><code>class FileClassTest extends Specification { FileClass fileClass def "test simple object"() { def listObjects = [] SimpleObject object1 = new SimpleObject(objectName: "First object", objectContent: "First object content") SimpleObject object2 = new SimpleObject(objectName: "Second object", objectContent: "Second object content") SimpleObject object3 = new SimpleObject(objectName: "Third object", objectContent: "Third object content") SimpleObject object4 = new SimpleObject(objectName: "Fourth object", objectContent: "Fourth object content") listObjects &lt;&lt; object1 listObjects &lt;&lt; object2 listObjects &lt;&lt; object3 listObjects &lt;&lt; object4 fileClass = new FileClass(listObjects: listObjects, basePath: ".") def dummyFile = new MockFor(File) def mockFile = new MockFor(File, true) //Intercept constructor call mockFile.demand.with { File() {dummyFile} } when: mockFile.use { fileClass.createFilePerObject() } then: 1 * mockFile.write(_) } } </code></pre> <p>So, as you can see, im trying to verify that new files actually have something written in them.</p> <p>And, i get the following error:</p> <pre><code>MockFor with constructor interception enabled is only allowed for Groovy objects but found: java.io.File </code></pre> <p>So, File is, as i understand, extended in groovy GDK(Groovy JDK), and it has additional(and very helpful) methods. But Groovy tries to mock java.io.File.</p> <p>And, following the logic of the error, i decided to actually ovveride the File constructor like this:</p> <pre><code>class FileClassTest extends Specification { FileClass fileClass def "test simple object"() { def listObjects = [] SimpleObject object1 = new SimpleObject(objectName: "First object", objectContent: "First object content") SimpleObject object2 = new SimpleObject(objectName: "Second object", objectContent: "Second object content") SimpleObject object3 = new SimpleObject(objectName: "Third object", objectContent: "Third object content") SimpleObject object4 = new SimpleObject(objectName: "Fourth object", objectContent: "Fourth object content") listObjects &lt;&lt; object1 listObjects &lt;&lt; object2 listObjects &lt;&lt; object3 listObjects &lt;&lt; object4 fileClass = new FileClass(basePath: ".", listObjects: listObjects) def mockFile = new MockFor(File) File.metaClass.constructor &lt;&lt; {String filePath -&gt; mockFile } //Return the mocked file, so it can be verified when: mockFile.use { fileClass.createFilePerObject() } then: 1 * mockFile.write(_) } } </code></pre> <p>And recived the warning that the constructor already exists(i guess i cant ovveride it after all):</p> <pre><code>groovy.lang.GroovyRuntimeException: Cannot add new constructor for arguments [[class java.lang.String]]. It already exists! </code></pre> <p>So, one of the ideas is to actually mock the File Factory that would produce the new File objects in the loop. However, the factory is, to say the least, useless - it would be used only to have the ability to test the file creation.</p> <p>So, PowerMock doesnt work(cant load PowerMockRunner), any ideas how to mock this, not using additional libraries, and not end up with useless classes?</p> <p>Thanks.</p>
 

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