diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java
index 11100b63c..c1b6cb259 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java
@@ -45,6 +45,7 @@ package org.eclipse.jgit.lib;
 import static java.lang.Long.valueOf;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
@@ -53,10 +54,12 @@ import java.io.IOException;
 import java.util.TreeSet;
 
 import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
 import org.eclipse.jgit.treewalk.FileTreeIteratorWithTimeControl;
 import org.eclipse.jgit.treewalk.NameConflictTreeWalk;
+import org.eclipse.jgit.treewalk.WorkingTreeOptions;
 import org.eclipse.jgit.util.FileUtils;
 import org.junit.Test;
 
@@ -137,8 +140,8 @@ public class RacyGitTests extends RepositoryTestCase {
 		fsTick(db.getIndexFile());
 
 		// create two files
-		File a = addToWorkDir("a", "a");
-		File b = addToWorkDir("b", "b");
+		File a = writeToWorkDir("a", "a");
+		File b = writeToWorkDir("b", "b");
 		assertTrue(a.setLastModified(b.lastModified()));
 		assertTrue(b.setLastModified(b.lastModified()));
 
@@ -158,23 +161,35 @@ public class RacyGitTests extends RepositoryTestCase {
 		fsTick(db.getIndexFile());
 
 		// Create a racy git situation. This is a situation that the index is
-		// updated and then a file is modified within a second. By changing the
-		// index file artificially, we create a fake racy situation.
-		File updatedA = addToWorkDir("a", "a2");
-		assertTrue(updatedA.setLastModified(updatedA.lastModified() + 100));
+		// updated and then a file is modified within the same tick of the
+		// filesystem timestamp resolution. By changing the index file
+		// artificially, we create a fake racy situation.
+		File updatedA = writeToWorkDir("a", "a2");
+		long newLastModified = updatedA.lastModified() + 100;
+		assertTrue(updatedA.setLastModified(newLastModified));
 		resetIndex(new FileTreeIterator(db));
-		assertTrue(db.getIndexFile()
-				.setLastModified(updatedA.lastModified() + 90));
+		assertTrue(db.getIndexFile().setLastModified(newLastModified));
 
-		db.readDirCache();
-		// although racily clean a should not be reported as being dirty
+		DirCache dc = db.readDirCache();
+		// check index state: although racily clean a should not be reported as
+		// being dirty since we forcefully reset the index to match the working
+		// tree
 		assertEquals(
 				"[a, mode:100644, time:t1, smudged, length:0, content:a2]"
 						+ "[b, mode:100644, time:t0, length:1, content:b]",
 				indexState(SMUDGE | MOD_TIME | LENGTH | CONTENT));
+
+		// compare state of files in working tree with index to check that
+		// FileTreeIterator.isModified() works as expected
+		FileTreeIterator f = new FileTreeIterator(db.getWorkTree(), db.getFS(),
+				db.getConfig().get(WorkingTreeOptions.KEY));
+		assertTrue(f.findFile("a"));
+		try (ObjectReader reader = db.newObjectReader()) {
+			assertFalse(f.isModified(dc.getEntry("a"), false, reader));
+		}
 	}
 
-	private File addToWorkDir(String path, String content) throws IOException {
+	private File writeToWorkDir(String path, String content) throws IOException {
 		File f = new File(db.getWorkTree(), path);
 		try (FileOutputStream fos = new FileOutputStream(f)) {
 			fos.write(content.getBytes(UTF_8));