Measure filesystem timestamp resolution already in test setup

This helps to avoid some time critical tests can't prepare the test
fixture intended since measuring timestamp resolution takes time.

Change-Id: Ib34023e682a106070ca97e98ef16789a4dfb97b4
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.ant.test/src/org/eclipse/jgit/ant/tasks/GitCloneTaskTest.java

@@ -65,12 +65,13 @@ public class GitCloneTaskTest extends LocalDiskRepositoryTestCase {
 
 	@Before
 	public void before() throws IOException {
+		dest = createTempFile();
+		FS.getFsTimerResolution(dest.toPath().getParent());
 		project = new Project();
 		project.init();
 		enableLogging();
 		project.addTaskDefinition("git-clone", GitCloneTask.class);
 		task = (GitCloneTask) project.createTask("git-clone");
-		dest = createTempFile();
 		task.setDest(dest);
 	}
 

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/LocalDiskRepositoryTestCase.java

@@ -127,6 +127,10 @@ public abstract class LocalDiskRepositoryTestCase {
 		if (!tmp.delete() || !tmp.mkdir())
 			throw new IOException("Cannot create " + tmp);
 
+		// measure timer resolution before the test to avoid time critical tests
+		// are affected by time needed for measurement
+		FS.getFsTimerResolution(tmp.toPath().getParent());
+
 		mockSystemReader = new MockSystemReader();
 		mockSystemReader.userGitConfig = new FileBasedConfig(new File(tmp,
 				"usergitconfig"), FS.DETECTED);

org.eclipse.jgit.lfs.server.test/tst/org/eclipse/jgit/lfs/server/fs/LfsServerTest.java

@@ -82,6 +82,7 @@ import org.eclipse.jgit.lfs.lib.LongObjectId;
 import org.eclipse.jgit.lfs.server.LargeFileRepository;
 import org.eclipse.jgit.lfs.server.LfsProtocolServlet;
 import org.eclipse.jgit.lfs.test.LongObjectIdTestUtils;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.IO;
 import org.junit.After;
@@ -119,6 +120,11 @@ public abstract class LfsServerTest {
 	@Before
 	public void setup() throws Exception {
 		tmp = Files.createTempDirectory("jgit_test_");
+
+		// measure timer resolution before the test to avoid time critical tests
+		// are affected by time needed for measurement
+		FS.getFsTimerResolution(tmp.getParent());
+
 		server = new AppServer();
 		ServletContextHandler app = server.addContext("/lfs");
 		dir = Paths.get(tmp.toString(), "lfs");

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/FileSnapshotTest.java

@@ -69,6 +69,9 @@ public class FileSnapshotTest {
 	@Before
 	public void setUp() throws Exception {
 		trash = Files.createTempDirectory("tmp_");
+		// measure timer resolution before the test to avoid time critical tests
+		// are affected by time needed for measurement
+		FS.getFsTimerResolution(trash.getParent());
 	}
 
 	@Before

org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/FileBasedConfigTest.java

@@ -83,6 +83,7 @@ public class FileBasedConfigTest {
 	@Before
 	public void setUp() throws Exception {
 		trash = Files.createTempDirectory("tmp_");
+		FS.getFsTimerResolution(trash.getParent());
 	}
 
 	@After