diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 6e69a2c5ba..a4b416420d 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -1,8 +1,11 @@
 package sonia.scm.repository.spi;
 
+import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.merge.MergeStrategy;
 import org.eclipse.jgit.merge.ResolveMerger;
 import org.eclipse.jgit.lib.Repository;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import sonia.scm.repository.GitWorkdirFactory;
 import sonia.scm.repository.InternalRepositoryException;
 import sonia.scm.repository.api.MergeCommandResult;
@@ -12,23 +15,20 @@ import java.io.IOException;
 
 public class GitMergeCommand extends AbstractGitCommand implements MergeCommand {
 
-  private final GitWorkdirFactory workdirPool;
+  private static final Logger logger = LoggerFactory.getLogger(GitMergeCommand.class);
 
-  GitMergeCommand(GitContext context, sonia.scm.repository.Repository repository, GitWorkdirFactory workdirPool) {
+  private final GitWorkdirFactory workdirFactory;
+
+  GitMergeCommand(GitContext context, sonia.scm.repository.Repository repository, GitWorkdirFactory workdirFactory) {
     super(context, repository);
-    this.workdirPool = workdirPool;
+    this.workdirFactory = workdirFactory;
   }
 
   @Override
   public MergeCommandResult merge(MergeCommandRequest request) {
-    try (WorkingCopy workingCopy = workdirPool.createWorkingCopy(context)) {
+    try (WorkingCopy workingCopy = workdirFactory.createWorkingCopy(context)) {
       Repository repository = workingCopy.get();
-      ResolveMerger merger = (ResolveMerger) MergeStrategy.RECURSIVE.newMerger(repository);
-      boolean mergeResult = merger.merge(repository.resolve(request.getBranchToMerge()), repository.resolve(request.getTargetBranch()));
-      if (mergeResult) {
-        // TODO push and verify push was successful
-      }
-      return new MergeCommandResult(mergeResult);
+      return new MergeWorker(repository).merge(request);
     } catch (IOException e) {
       throw new InternalRepositoryException(e);
     }
@@ -44,4 +44,34 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
       throw new InternalRepositoryException(e);
     }
   }
+
+  private static class MergeWorker {
+
+    private final Repository clone;
+    private MergeWorker(Repository clone) {
+      this.clone = clone;
+    }
+
+    private MergeCommandResult merge(MergeCommandRequest request) throws IOException {
+      ResolveMerger merger = (ResolveMerger) MergeStrategy.RECURSIVE.newMerger(clone);
+      boolean mergeResult = merger.merge(
+        resolveRevision(clone, request.getTargetBranch()),
+        resolveRevision(clone, request.getBranchToMerge())
+      );
+      if (mergeResult) {
+        logger.info("Merged branch {} into {}", request.getBranchToMerge(), request.getTargetBranch());
+        // TODO commit, push and verify push was successful
+      }
+      return new MergeCommandResult(mergeResult);
+    }
+
+    private ObjectId resolveRevision(Repository repository, String branchToMerge) throws IOException {
+      ObjectId resolved = repository.resolve(branchToMerge);
+      if (resolved == null) {
+        return repository.resolve("origin/" + branchToMerge);
+      } else {
+        return resolved;
+      }
+    }
+  }
 }
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index 3c58916807..bd140c68cb 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -3,7 +3,22 @@ package sonia.scm.repository.spi;
 import org.junit.Assert;
 import org.junit.Test;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
 public class GitMergeCommandTest extends AbstractGitCommandTestBase {
+
+  @Test
+  public void shouldDetectMergeableBranches() {
+    GitMergeCommand command = createCommand();
+    MergeCommandRequest request = new MergeCommandRequest();
+    request.setBranchToMerge("mergeable");
+    request.setTargetBranch("master");
+
+    boolean mergeable = command.dryRun(request).isMergeable();
+
+    assertThat(mergeable).isTrue();
+  }
+
   @Test
   public void shouldDetectNotMergeableBranches() {
     GitMergeCommand command = createCommand();
@@ -13,10 +28,34 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
 
     boolean mergeable = command.dryRun(request).isMergeable();
 
-    Assert.assertFalse(mergeable);
+    assertThat(mergeable).isFalse();
+  }
+
+  @Test
+  public void shouldMergeMergeableBranches() {
+    GitMergeCommand command = createCommand();
+    MergeCommandRequest request = new MergeCommandRequest();
+    request.setTargetBranch("master");
+    request.setBranchToMerge("mergeable");
+
+    boolean mergeable = command.merge(request).isSuccess();
+
+    assertThat(mergeable).isTrue();
+  }
+
+  @Test
+  public void shouldNotMergeConflictingBranches() {
+    GitMergeCommand command = createCommand();
+    MergeCommandRequest request = new MergeCommandRequest();
+    request.setBranchToMerge("test-branch");
+    request.setTargetBranch("master");
+
+    boolean mergeable = command.merge(request).isSuccess();
+
+    assertThat(mergeable).isFalse();
   }
 
   private GitMergeCommand createCommand() {
-    return new GitMergeCommand(createContext(), repository, null);
+    return new GitMergeCommand(createContext(), repository, new SimpleGitWorkdirFactory());
   }
 }
diff --git a/scm-plugins/scm-git-plugin/src/test/resources/sonia/scm/repository/spi/scm-git-spi-test.zip b/scm-plugins/scm-git-plugin/src/test/resources/sonia/scm/repository/spi/scm-git-spi-test.zip
index 3fbab0be38..8f689e9664 100644
Binary files a/scm-plugins/scm-git-plugin/src/test/resources/sonia/scm/repository/spi/scm-git-spi-test.zip and b/scm-plugins/scm-git-plugin/src/test/resources/sonia/scm/repository/spi/scm-git-spi-test.zip differ