neovim.tests: test lua transitive deps are available

As reported in several issues, lua plugin dependencies are not visible
from neovim. This adds a test to make sure nvim can see jsregexp when luasnip is part of the wrapper
see https://github.com/NixOS/nixpkgs/issues/306367 or https://github.com/NixOS/nixpkgs/issues/318925
for details

pkgs/applications/editors/neovim/tests/default.nix

@@ -43,6 +43,14 @@ let
     '';
   };
 
+  nvim-with-luasnip = wrapNeovim2 "-with-lua-packages" (makeNeovimConfig {
+    plugins = [ {
+        plugin = vimPlugins.luasnip;
+
+      }
+    ];
+  });
+
   nvimAutoDisableWrap = makeNeovimConfig { };
 
   wrapNeovim2 = suffix: config:
@@ -281,4 +289,16 @@ rec {
     export HOME=$TMPDIR
     ${nvim_with_opt_plugin}/bin/nvim -i NONE +quit! -e
   '';
+
+  inherit nvim-with-luasnip;
+
+  # check that bringing in one plugin with lua deps makes those deps visible from wrapper
+  # for instance luasnip has a dependency on jsregexp
+  can_require_transitive_deps =
+    runTest nvim-with-luasnip ''
+    export HOME=$TMPDIR
+    cat ${nvim-with-luasnip}/bin/nvim
+    ${nvim-with-luasnip}/bin/nvim -i NONE --cmd "lua require'jsregexp'" -e
+  '';
+
 })