Teach check-large-files-added about git-lfs. Reslves #82.

get-git-lfs.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3.4
+"""This is a script to install git-lfs to a tempdir for use in tests"""
+import io
+import os.path
+import shutil
+import tarfile
+from urllib.request import urlopen
+
+DOWNLOAD_PATH = (
+    'https://github.com/github/git-lfs/releases/download/'
+    'v1.1.0/git-lfs-linux-amd64-1.1.0.tar.gz'
+)
+PATH_IN_TAR = 'git-lfs-1.1.0/git-lfs'
+DEST_PATH = '/tmp/git-lfs/git-lfs'
+DEST_DIR = os.path.dirname(DEST_PATH)
+
+
+def main():
+    if (
+            os.path.exists(DEST_PATH) and
+            os.path.isfile(DEST_PATH) and
+            os.access(DEST_PATH, os.X_OK)
+    ):
+        print('Already installed!')
+        return 0
+
+    shutil.rmtree(DEST_DIR, ignore_errors=True)
+    os.makedirs(DEST_DIR, exist_ok=True)
+
+    contents = io.BytesIO(urlopen(DOWNLOAD_PATH).read())
+    with tarfile.open(fileobj=contents) as tar:
+        with tar.extractfile(PATH_IN_TAR) as src_file:
+            with open(DEST_PATH, 'wb') as dest_file:
+                shutil.copyfileobj(src_file, dest_file)
+    os.chmod(DEST_PATH, 0o755)
+
+if __name__ == '__main__':
+    exit(main())