diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/OpenSshConfigTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/OpenSshConfigTest.java
index 7777a3c99..0358718cf 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/OpenSshConfigTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/OpenSshConfigTest.java
@@ -58,6 +58,7 @@
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.time.Instant;
+import java.util.concurrent.TimeUnit;
 
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.lib.Constants;
@@ -93,12 +94,17 @@ public void setUp() throws Exception {
 	}
 
 	private void config(String data) throws IOException {
-		FS fs = db.getFS();
+		FS fs = FS.DETECTED;
+		long resolution = FS.getFileStoreAttributes(configFile.toPath())
+				.getFsTimestampResolution().toNanos();
 		Instant lastMtime = fs.lastModifiedInstant(configFile);
 		do {
 			try (final OutputStreamWriter fw = new OutputStreamWriter(
 					new FileOutputStream(configFile), UTF_8)) {
 				fw.write(data);
+				TimeUnit.NANOSECONDS.sleep(resolution);
+			} catch (InterruptedException e) {
+				Thread.interrupted();
 			}
 		} while (lastMtime.equals(fs.lastModifiedInstant(configFile)));
 	}