tests/enable-except-in-tests: refactor

More explicitly assert that `enableExceptInTests` is the expected value.

tests/enable-except-in-tests.nix

@@ -1,4 +1,5 @@
 {
+  lib,
   pkgs,
   linkFarm,
   runCommandLocal,
@@ -6,30 +7,61 @@
   makeNixvimWithModule,
 }:
 let
-  module =
-    { helpers, ... }:
-    {
-      plugins.image.enable = helpers.enableExceptInTests;
-    };
-
   inTest = mkTestDerivationFromNixvimModule {
     name = "enable-except-in-tests-test";
-    inherit pkgs module;
+    inherit pkgs;
+    module =
+      { lib, helpers, ... }:
+      {
+        assertions = [
+          {
+            # FIXME: should be false
+            assertion = lib.nixvim.enableExceptInTests;
+            message = "Expected lib.nixvim.enableExceptInTests to be true";
+          }
+          {
+            assertion = !helpers.enableExceptInTests;
+            message = "Expected helpers.enableExceptInTests to be false";
+          }
+        ];
+      };
   };
 
   notInTest =
     let
-      nvim = makeNixvimWithModule { inherit pkgs module; };
+      nvim = makeNixvimWithModule {
+        inherit pkgs;
+        module =
+          { lib, helpers, ... }:
+          {
+            assertions = [
+              {
+                assertion = lib.nixvim.enableExceptInTests;
+                message = "Expected lib.nixvim.enableExceptInTests to be true";
+              }
+              {
+                assertion = helpers.enableExceptInTests;
+                message = "Expected helpers.enableExceptInTests to be true";
+              }
+            ];
+          };
+      };
     in
     runCommandLocal "enable-except-in-tests-not-in-test"
-      { printConfig = "${nvim}/bin/nixvim-print-init"; }
+      {
+        __structuredAttrs = true;
+        assertions = lib.pipe nvim.config.assertions [
+          (lib.filter (x: !x.assertion))
+          (lib.map (x: x.message))
+        ];
+      }
       ''
-        if ! "$printConfig" | grep 'require("image").setup'; then
+        if (( ''${#assertions[@]} )); then
-          echo "image.nvim is not present in the configuration"
+          for assertion in "''${assertions[@]}"; do
-          echo -e "configuration:\n$($printConfig)"
+            echo "- $assertion"
+          done
           exit 1
         fi
-
         touch $out
       '';
 in