--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/org/tmatesoft/hg/test/TestTransaction.java	Wed Jul 10 20:16:37 2013 +0200
@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2013 TMate Software Ltd
+ *  
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * For information on how to redistribute this software under
+ * the terms of a license other than GNU General Public License
+ * contact TMate Software at support@hg4j.com
+ */
+package org.tmatesoft.hg.test;
+
+import static org.junit.Assert.*;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.tmatesoft.hg.internal.BasicSessionContext;
+import org.tmatesoft.hg.internal.COWTransaction;
+import org.tmatesoft.hg.internal.Transaction;
+
+/**
+ * Check transaction rollback/commit as it's tricky to test transactions as part of pull/push commands
+ * 
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class TestTransaction {
+
+	@Rule
+	public ErrorCollectorExt errorCollector = new ErrorCollectorExt();
+	
+	@Test
+	public void testCopyOnWriteTransaction() throws Exception {
+		final BasicSessionContext ctx = new BasicSessionContext(null);
+		Transaction.Factory f = new COWTransaction.Factory();
+		File dir = RepoUtils.createEmptyDir("test-transaction-cow");
+		File f1 = new File(dir, "f1");
+		File f2 = new File(dir, "f2");
+		File f3 = new File(dir, "f3");
+		RepoUtils.createFile(f1, "1");
+		assertTrue(f1.exists());
+		assertFalse(f2.exists());
+		assertFalse(f3.exists());
+		//
+		// transaction commit
+		Transaction tr1 = f.create(ctx);
+		File tf1 = tr1.prepare(f1);
+		RepoUtils.modifyFileAppend(tf1, "2");
+		tr1.done(tf1);
+		File tf2 = tr1.prepare(f2);
+		errorCollector.assertTrue(tf2.exists());
+		RepoUtils.modifyFileAppend(tf2, "A");
+		tr1.done(tf2);
+		tr1.commit();
+		errorCollector.assertTrue(f1.isFile());
+		errorCollector.assertTrue(f2.isFile());
+		errorCollector.assertEquals("12", read(f1));
+		errorCollector.assertEquals("A", read(f2));
+		//
+		// transaction rollback
+		assertFalse(f3.exists());
+		Transaction tr2 = f.create(ctx);
+		tf1 = tr2.prepare(f1);
+		RepoUtils.modifyFileAppend(tf1, "3");
+		tr2.done(tf1);
+		errorCollector.assertEquals("123", read(tf1));
+		tf2 = tr2.prepare(f2);
+		RepoUtils.modifyFileAppend(tf2, "B");
+		tr2.done(tf2);
+		errorCollector.assertEquals("AB", read(tf2));
+		File tf3 = tr2.prepare(f3);
+		errorCollector.assertTrue(tf3.exists());
+		RepoUtils.modifyFileAppend(tf3, "!");
+		tr2.done(tf3);
+		errorCollector.assertEquals("!", read(tf3));
+		tr2.rollback();
+		errorCollector.assertTrue(f1.isFile());
+		errorCollector.assertTrue(f2.isFile());
+		errorCollector.assertFalse(f3.isFile());
+		errorCollector.assertEquals("12", read(f1));
+		errorCollector.assertEquals("A", read(f2));
+	}
+
+	String read(File f) throws IOException {
+		StringBuilder sb = new StringBuilder();
+		FileReader fr = new FileReader(f);
+		int ch;
+		while ((ch = fr.read()) != -1) {
+			sb.append((char) ch);
+		}
+		fr.close();
+		return sb.toString();
+	}
+}