diff --git a/plugins/git4idea/tests/git4idea/test/GitMockRepositoryManager.java b/plugins/git4idea/tests/git4idea/test/GitMockRepositoryManager.java
index 261422b7be89..59cb42dc025f 100644
--- a/plugins/git4idea/tests/git4idea/test/GitMockRepositoryManager.java
+++ b/plugins/git4idea/tests/git4idea/test/GitMockRepositoryManager.java
@@ -59,6 +59,21 @@ public class GitMockRepositoryManager implements RepositoryManager<GitRepository
     return myRepositories;
   }
 
+  @Override
+  public void addExternalRepository(@NotNull VirtualFile root, @NotNull GitRepository repository) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void removeExternalRepository(@NotNull VirtualFile root) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean isExternal(@NotNull GitRepository repository) {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public boolean moreThanOneRoot() {
     return myRepositories.size() > 1;