Fix the way unit tests modify the timestamp of a file

src/test/java/org/codehaus/plexus/archiver/BasePlexusArchiverTest.java

@@ -24,6 +24,10 @@
 package org.codehaus.plexus.archiver;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.attribute.FileTime;
+
 import org.codehaus.plexus.PlexusTestCase;
 import org.codehaus.plexus.util.FileUtils;
 
@@ -35,31 +39,54 @@ public abstract class BasePlexusArchiverTest extends PlexusTestCase
 {
 
     /**
-     * Ensure that when a new file is created at the specified location that the timestamp of
-     * that file will be greater than the one specified as a reference.
-     *
-     * Warning: Runs in a busy loop creating a file until the output file is newer than the reference timestamp.
-     * This should be better than sleeping for a race condition time out value.
+     * Ensure that the last modified timestamp of a file will be greater
+     * than the one specified as a reference.
      *
-     * @param outputFile the file to be created
-     * @param timestampReference the created file will have a newer timestamp than this reference timestamp.
+     * @param outputFile the file
+     * @param timestampReference the file will have a newer timestamp
+     *        than this reference timestamp.
      *
-     * @throws Exception failures
+     * @throws IOException if the timestamp could not be modified
      */
-    protected void waitUntilNewTimestamp( File outputFile, long timestampReference ) throws Exception
+    protected void waitUntilNewTimestamp( File outputFile, long timestampReference )
+        throws IOException
     {
-        File tmpFile = File.createTempFile( "ZipArchiverTest.waitUntilNewTimestamp", null );
-        // slurp the file into a temp file and then copy the temp back over the top until it is newer.
-        FileUtils.copyFile( outputFile, tmpFile );
+        long startTime = System.currentTimeMillis();
+        File tmpFile = File.createTempFile(
+            "BasePlexusArchiverTest.waitUntilNewTimestamp", null );
+        long newTimestamp;
 
-        FileUtils.copyFile( tmpFile, outputFile );
-        while ( timestampReference >= outputFile.lastModified() )
+        // We could easily just set the last modified time using
+        // Files.setLastModifiedTime and System.currentTimeMillis(),
+        // but the problem is that tests are using this method to verify that
+        // the force flag is working. To ensure that modified or
+        // newly created files will have timestamp newer than
+        // `timestampReference`, we need to modify a file ourself.
+        // Otherwise the build may fail because when the test overrides
+        // `outputFile` it will have timestamp that is equal
+        // to `timestampReference`.
+        do
         {
-            FileUtils.copyFile( tmpFile, outputFile );
+            FileUtils.fileWrite( tmpFile, "waitUntilNewTimestamp" );
+            newTimestamp = tmpFile.lastModified();
             Thread.yield();
         }
+        while ( timestampReference >= newTimestamp
+                // A simple guard to ensure that we'll not do this forever.
+                // If the last modified timestamp is not changed to
+                // a newer value after 10 seconds, probably it never will.
+                && System.currentTimeMillis() - startTime < 10_000 );
 
         tmpFile.delete();
+
+        if ( timestampReference >= newTimestamp )
+        {
+            throw new IOException("Could not modify the last modified timestamp "
+                + "to newer than the refence value." );
+        }
+
+        FileTime newTimestampTime = FileTime.fromMillis( newTimestamp );
+        Files.setLastModifiedTime( outputFile.toPath(), newTimestampTime );
     }
 
     /**