diff --git a/MANIFEST.in b/MANIFEST.in
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -5,5 +5,6 @@
 include conftest.py
 recursive-include swh/loader/package/tests/ *.tar.gz
 recursive-include swh py.typed
+recursive-include swh/loader/tests/data/ *
 recursive-include swh/loader/package/tests/data/ *
 recursive-include swh/loader/package/*/tests/data/ *
diff --git a/swh/loader/core/tests/__init__.py b/swh/loader/core/tests/__init__.py
--- a/swh/loader/core/tests/__init__.py
+++ b/swh/loader/core/tests/__init__.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2018  The Software Heritage developers
+# Copyright (C) 2018-2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
diff --git a/swh/loader/tests/__init__.py b/swh/loader/tests/__init__.py
--- a/swh/loader/tests/__init__.py
+++ b/swh/loader/tests/__init__.py
@@ -0,0 +1,31 @@
+# Copyright (C) 2018-2020  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import os
+import subprocess
+
+from pathlib import PosixPath
+from typing import Optional, Union
+
+
+def prepare_repository_from_archive(
+    archive_path: str,
+    filename: Optional[str] = None,
+    tmp_path: Union[PosixPath, str] = "/tmp",
+) -> str:
+    """Given an existing archive_path, uncompress it.
+    Returns a file repo url which can be used as origin url.
+
+    This does not deal with the case where the archive passed along does not exist.
+
+    """
+    if not isinstance(tmp_path, str):
+        tmp_path = str(tmp_path)
+    # uncompress folder/repositories/dump for the loader to ingest
+    subprocess.check_output(["tar", "xf", archive_path, "-C", tmp_path])
+    # build the origin url (or some derivative form)
+    _fname = filename if filename else os.path.basename(archive_path)
+    repo_url = f"file://{tmp_path}/{_fname}"
+    return repo_url
diff --git a/swh/loader/tests/data/0805nexter-1.1.0.tar.gz b/swh/loader/tests/data/0805nexter-1.1.0.tar.gz
new file mode 120000
--- /dev/null
+++ b/swh/loader/tests/data/0805nexter-1.1.0.tar.gz
@@ -0,0 +1 @@
+../../package/pypi/tests/data/https_files.pythonhosted.org/0805nexter-1.1.0.tar.gz
\ No newline at end of file
diff --git a/swh/loader/tests/test_init.py b/swh/loader/tests/test_init.py
new file mode 100644
--- /dev/null
+++ b/swh/loader/tests/test_init.py
@@ -0,0 +1,50 @@
+# Copyright (C) 2020  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import os
+import subprocess
+
+import pytest
+
+from swh.loader.tests import prepare_repository_from_archive
+
+
+def test_prepare_repository_from_archive_failure():
+    # does not deal with inexistent archive so raise
+    assert os.path.exists("unknown-archive") is False
+    with pytest.raises(subprocess.CalledProcessError, match="exit status 2"):
+        prepare_repository_from_archive("unknown-archive")
+
+
+def test_prepare_repository_from_archive(datadir, tmp_path):
+    archive_name = "0805nexter-1.1.0"
+    archive_path = os.path.join(str(datadir), f"{archive_name}.tar.gz")
+    assert os.path.exists(archive_path) is True
+
+    tmp_path = str(tmp_path)  # deals with path string
+    repo_url = prepare_repository_from_archive(
+        archive_path, filename=archive_name, tmp_path=tmp_path
+    )
+    expected_uncompressed_archive_path = os.path.join(tmp_path, archive_name)
+    assert repo_url == f"file://{expected_uncompressed_archive_path}"
+    assert os.path.exists(expected_uncompressed_archive_path)
+
+
+def test_prepare_repository_from_archive_no_filename(datadir, tmp_path):
+    archive_name = "0805nexter-1.1.0"
+    archive_path = os.path.join(str(datadir), f"{archive_name}.tar.gz")
+    assert os.path.exists(archive_path) is True
+
+    # deals with path as posix path (for tmp_path)
+    repo_url = prepare_repository_from_archive(archive_path, tmp_path=tmp_path)
+
+    tmp_path = str(tmp_path)
+    expected_uncompressed_archive_path = os.path.join(tmp_path, archive_name)
+    expected_repo_url = os.path.join(tmp_path, f"{archive_name}.tar.gz")
+    assert repo_url == f"file://{expected_repo_url}"
+
+    # passing along the filename does not influence the on-disk extraction
+    # just the repo-url computation
+    assert os.path.exists(expected_uncompressed_archive_path)