Instances created with a given constructor not working for java.io.File

[rjh1970]

Please provide the following information:

• Version of JMockit that was used: 1.40. TestNG: 6.14.3

• Description of the problem:

Using the pattern shown in the tutorial for "Instances created with a given constructor", I can't successfully mock separate instances of java.io.File whereas I can successfully mock a dummy class with the same constructor/method. The example included shows that a test fails when an expectation on the File instance is not met for file1.exists(); due to a missing invocation but passes for the DummyFile instance. I have attempted to reduce the code to the minimum amount to reproduce the problem. Apologies if I have made an elementary mistake - I'm new to JMockit. Code and results are below:

package test;

import java.io.File;

import org.testng.Assert;
import org.testng.annotations.Test;

import mockit.Expectations;
import mockit.Mocked;

public class TestFileTest {

    static class DummyFile {
        final String filename;

        DummyFile(String filename) {
            this.filename = filename;
        }

        boolean exists() {
            return true;
        }
    }

    public static String fileName1 = "a.txt";
    public static String fileName2 = "b.txt";

    @Test
    public void DoTest(@Mocked File file1, @Mocked File file2) {
        new Expectations() {
            {
                new File(fileName1);
                result = file1;
                new File(fileName2);
                result = file2;

                file1.exists();
                result = false;

                file2.exists();
                result = false;
            }
        };

        Assert.assertFalse(new File(fileName1).exists());
        Assert.assertFalse(new File(fileName2).exists());

    }

    @Test
    public void DoDummyTest(@Mocked DummyFile file1, @Mocked DummyFile file2) {
        new Expectations() {
            {
                new DummyFile(fileName1);
                result = file1;
                new DummyFile(fileName2);
                result = file2;

                file1.exists();
                result = false;

                file2.exists();
                result = false;
            }
        };

        Assert.assertFalse(new DummyFile(fileName1).exists());
        Assert.assertFalse(new DummyFile(fileName2).exists());

    }
}

[RemoteTestNG] detected TestNG version 6.14.3
PASSED: DoDummyTest
FAILED: DoTest
Missing 1 invocation to:
java.io.File#exists()
   on mock instance: java.io.File@17baae6e
Caused by: Missing invocations
	at java.io.File.exists(File.java)
	at com.ibm.watson.voyager.syncer.health.TestFileTest$1.<init>(TestFileTest.java:37)
	at com.ibm.watson.voyager.syncer.health.TestFileTest.DoTest(TestFileTest.java:30)


===============================================
    Default test
    Tests run: 2, Failures: 1, Skips: 0
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Default suite
Total tests run: 2, Failures: 1, Skips: 0
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