e2e test for gitlfs

tests/nixos/fetch-git/test-cases/lfs/default.nix

@@ -0,0 +1,70 @@
+{
+  # mostly copied from https://github.com/NixOS/nix/blob/358c26fd13a902d9a4032a00e6683571be07a384/tests/nixos/fetch-git/test-cases/fetchTree-shallow/default.nix#L1
+  # ty @DavHau
+  description = "fetchGit with lfs=true smudges LFS pointers";
+  script = ''
+    # purge nix git cache to make sure we start with a clean slate
+    client.succeed("rm -rf ~/.cache/nix")
+
+    # add two commits to the repo:
+    client.succeed(f"""
+      dd if=/dev/urandom of={repo.path}/beeg bs=1M count=1 \
+      && {repo.git} lfs track "beeg" \
+      && {repo.git} add .gitattributes \
+      && {repo.git} add beeg \
+      && {repo.git} commit -m 'commit1' \
+      && {repo.git} push origin main
+    """)
+
+    # memoize the revision
+    commit1_rev = client.succeed(f"""
+      {repo.git} rev-parse HEAD
+    """).strip()
+
+    # first fetch without lfs, check that we did not smudge the file
+    fetchGit_nolfs_expr = f"""
+      builtins.fetchGit {{
+        type = "git";
+        url = "{repo.remote}";
+        rev = "{commit1_rev}";
+        lfs = false;
+      }}
+    """
+
+    # fetch the repo via nix
+    fetched_nolfs = client.succeed(f"""
+      nix eval --impure --raw --expr '({fetchGit_nolfs_expr}).outPath'
+    """)
+
+    # check that file was not smudged
+    file_size_nolfs = client.succeed(f"""
+      stat -c %s {fetched_nolfs}/beeg
+    """).strip()
+
+    expected_max_size_lfs = 1024
+    assert int(file_size_nolfs) < expected_max_size_lfs, f"lfs-enrolled file bigger than {expected_max_size_lfs}, file was probably smudged but we did not set lfs=true"
+
+    # now fetch with lfs=true and check that the file was smudged
+    fetchGit_lfs_expr = f"""
+      builtins.fetchGit {{
+        type = "git";
+        url = "{repo.remote}";
+        rev = "{commit1_rev}";
+        lfs = true;
+      }}
+    """
+
+    # fetch the repo via nix
+    fetched_lfs = client.succeed(f"""
+      nix eval --impure --raw --expr '({fetchGit_lfs_expr}).outPath'
+    """)
+
+    # check that file was smudged
+    file_size_lfs = client.succeed(f"""
+      stat -c %s {fetched_lfs}/beeg
+    """).strip()
+
+    expected_min_size_lfs = 1024 * 1024  # 1MB
+    assert int(file_size_lfs) >= expected_min_size_lfs, f"lfs-enrolled file smaller than {expected_min_size_lfs}, file was probably not smudged despite lfs=true"
+  '';
+}

tests/nixos/fetch-git/testsupport/gitea.nix

@@ -38,7 +38,7 @@ in {
       });
     };
     client = { pkgs, ... }: {
-      environment.systemPackages = [ pkgs.git ];
+      environment.systemPackages = [ pkgs.git pkgs.git-lfs ];
     };
   };
   defaults = { pkgs, ... }: {