We pull Postgres from Nix using rules_nixpkgs for our Bazel tests. It works pretty well. I wrote some additional infrastructure that makes it easy to test again

We pull Postgres from Nix using rules_nixpkgs for our Bazel tests. It works pretty well. I wrote some additional infrastructure that makes it easy to test against different versions of postgres (11, 12, 13 - all available from Nix) using simple Bazel command line options.