--- a/test/org/tmatesoft/hg/test/TestCommit.java	Tue Feb 05 20:06:22 2013 +0100
+++ b/test/org/tmatesoft/hg/test/TestCommit.java	Tue Feb 05 22:30:21 2013 +0100
@@ -16,8 +16,14 @@
  */
 package org.tmatesoft.hg.test;
 
-import org.junit.Assert;
+import java.io.File;
+import java.io.FileWriter;
+import java.nio.ByteBuffer;
+
 import org.junit.Test;
+import org.tmatesoft.hg.repo.CommitFacility;
+import org.tmatesoft.hg.repo.HgLookup;
+import org.tmatesoft.hg.repo.HgRepository;
 
 /**
  * 
@@ -27,7 +33,61 @@
 public class TestCommit {
 
 	@Test
-	public void testCommitToEmpty() throws Exception {
-		Assert.fail();
+	public void testCommitToNonEmpty() throws Exception {
+		File repoLoc = RepoUtils.initEmptyTempRepo("test-commit2non-empty");
+		FileWriter fw = new FileWriter(new File(repoLoc, "file1"));
+		fw.write("hello");
+		fw.close();
+		new ExecHelper(new OutputParser.Stub(true), repoLoc).run("hg", "commit", "--addremove", "-m", "FIRST");
+		//
+		HgRepository hgRepo = new HgLookup().detect(repoLoc);
+		CommitFacility cf = new CommitFacility(hgRepo, 0 /*NO_REVISION*/);
+		// FIXME test diff for processing changed newlines - if a whole line or just changed endings are in the patch!
+		cf.add(hgRepo.getFileNode("file1"), new ByteArraySupplier("hello\nworld".getBytes()));
+		cf.commit("commit 1");
+		// /tmp/test-commit2non-empty/.hg/ store/data/file1.i dumpData
+	}
+	
+	public static void main(String[] args) throws Exception {
+		new TestCommit().testCommitToNonEmpty();
+		String input = "abcdefghijklmnopqrstuvwxyz";
+		ByteArraySupplier bas = new ByteArraySupplier(input.getBytes());
+		ByteBuffer bb = ByteBuffer.allocate(7);
+		byte[] result = new byte[26];
+		int rpos = 0;
+		while (bas.read(bb) != -1) {
+			bb.flip();
+			bb.get(result, rpos, bb.limit());
+			rpos += bb.limit();
+			bb.clear();
+		}
+		if (input.length() != rpos) {
+			throw new AssertionError();
+		}
+		String output = new String(result);
+		if (!input.equals(output)) {
+			throw new AssertionError();
+		}
+		System.out.println(output);
+	}
+
+	static class ByteArraySupplier implements CommitFacility.ByteDataSupplier {
+
+		private final byte[] data;
+		private int pos = 0;
+
+		public ByteArraySupplier(byte[] source) {
+			data = source;
+		}
+
+		public int read(ByteBuffer buf) {
+			if (pos >= data.length) {
+				return -1;
+			}
+			int count = Math.min(buf.remaining(), data.length - pos);
+			buf.put(data, pos, count);
+			pos += count;
+			return count;
+		}
 	}
 }