diff --git a/worker/jobs/pull/upload.py b/worker/jobs/pull/upload.py
index 84222c53f..bc11e50df 100644
--- a/worker/jobs/pull/upload.py
+++ b/worker/jobs/pull/upload.py
@@ -15,7 +15,7 @@ def pull_upload(source: dict, path: Optional[str] = None, **kwargs) -> Files:
     directory.
 
     In production, `source["url"]` is the URL (usually a storage bucket).
-    In development `source["path"]` is the path on the local file system.
+    In development, `source["path"]` is the path on the local file system.
     """
     if not path:
         src = source["path"] if "path" in source else source["url"]
diff --git a/worker/jobs/pull/upload_test.py b/worker/jobs/pull/upload_test.py
new file mode 100644
index 000000000..a523105ad
--- /dev/null
+++ b/worker/jobs/pull/upload_test.py
@@ -0,0 +1,48 @@
+from pathlib import Path
+
+import pytest
+
+from util.working_directory import working_directory
+
+from .upload import pull_upload
+
+
+def test_one(tempdir):
+    """
+    Test that will create new directories if necessary.
+    """
+    with working_directory(tempdir.path):
+        files = pull_upload(dict(path=__file__), "a/b/some.txt")
+
+    assert list(files.keys()) == ["a/b/some.txt"]
+    tempdir.compare(["a/", "a/b/", "a/b/some.txt"])
+
+
+def test_overwrite(tempdir):
+    """
+    Test that will overwrite any existing files.
+    """
+    with working_directory(tempdir.path):
+        with open("some.txt", "w") as file:
+            file.write("wateva")
+        assert open("some.txt").read() == "wateva"
+
+        files = pull_upload(dict(path=__file__), "some.txt")
+        assert open("some.txt").read().startswith("from pathlib")
+    assert list(files.keys()) == ["some.txt"]
+    tempdir.compare(["some.txt"])
+
+
+def test_mergedirs(tempdir):
+    """
+    Test that will merge with existing directories.
+    """
+    with working_directory(tempdir.path):
+        # A file that may have come from another source
+        Path("a/b").mkdir(parents=True, exist_ok=True)
+        with open("a/b/other.txt", "w") as file:
+            file.write("whateva")
+        # Pull an upload source into the same directory
+        files = pull_upload(dict(path=__file__), "a/b/some.txt")
+    assert list(files.keys()) == ["a/b/some.txt"]
+    tempdir.compare(["a/", "a/b/", "a/b/other.txt", "a/b/some.txt"])
diff --git a/worker/util/files.py b/worker/util/files.py
index efb7c0159..d587f601c 100644
--- a/worker/util/files.py
+++ b/worker/util/files.py
@@ -155,17 +155,24 @@ def remove_if_dir(path: str) -> None:
 
 def move_files(source: str, dest: str = ".", cleanup: bool = True) -> None:
     """
-    Move from `source` to `dest` directories (with overwrite).
-    """
-    for subpath in os.listdir(source):
-        source_path = os.path.join(source, subpath)
-        dest_path = os.path.join(dest, subpath)
-        if os.path.exists(dest_path):
-            if os.path.isdir(dest_path):
-                remove_dir(dest_path)
-        else:
-            ensure_parent(dest_path)
-        shutil.move(source_path, dest_path)
+    Move files from `source` to `dest` directories.
+
+    With overwrite of existing files, directory merging and (optional) cleanup
+    of the source.
+    """
+    for path, dirs, files in os.walk(source):
+        print(path, dirs, files)
+        rel_path = os.path.relpath(path, source)
+        dest_dir = os.path.join(dest, rel_path)
+        if not os.path.exists(dest_dir):
+            os.makedirs(dest_dir)
+        for file in files:
+            source_file = os.path.join(path, file)
+            dest_file = os.path.join(dest_dir, file)
+            if os.path.isfile(dest_file):
+                shutil.copy2(source_file, dest_file)
+            else:
+                os.rename(source_file, dest_file)
 
     if cleanup:
         remove_dir(source)