modules/test: check warnings/assertions

Warnings and assertions defined as `config.warnings` and `config.assertions`
respectively will be checked as part of the test derivation, instead of
when evaluating the modules.

Adds new `checkWarnings` and `checkAssertions` test options (default true).

lib/tests.nix

@@ -62,6 +62,9 @@ let
         extraSpecialArgs = {
           defaultPkgs = pkgs;
         } // extraSpecialArgs;
+        # Don't check assertions/warnings while evaluating nixvim config
+        # We'll let the test derivation handle that
+        check = false;
       };
     in
     result.config.test.derivation;

modules/top-level/test.nix

@@ -6,6 +6,9 @@
 }:
 let
   cfg = config.test;
+
+  inherit (config) warnings;
+  assertions = lib.nixvim.modules.getAssertionMessages config.assertions;
 in
 {
   options.test = {
@@ -21,6 +24,18 @@ in
       default = true;
     };
 
+    checkWarnings = lib.mkOption {
+      type = lib.types.bool;
+      description = "Whether to check `config.warnings` in the test.";
+      default = true;
+    };
+
+    checkAssertions = lib.mkOption {
+      type = lib.types.bool;
+      description = "Whether to check `config.assertions` in the test.";
+      default = true;
+    };
+
     # Output
     derivation = lib.mkOption {
       type = lib.types.package;
@@ -38,19 +53,42 @@ in
 
       nativeBuildInputs = [ config.finalPackage ];
 
-      # We need to set HOME because neovim will try to create some files
-      #
-      # Because neovim does not return an exitcode when quitting we need to check if there are
-      # errors on stderr
-      buildPhase = lib.optionalString cfg.runNvim ''
-        mkdir -p .cache/nvim
+      # First check warnings/assertions, then run nvim
+      buildPhase =
+        let
+          showErr =
+            name: lines:
+            lib.optionalString (lines != [ ]) ''
+              Unexpected ${name}:
+              ${lib.concatStringsSep "\n" (lib.map (v: "- ${v}") lines)}
+            '';
 
-        output=$(HOME=$(realpath .) nvim -mn --headless "+q" 2>&1 >/dev/null)
-        if [[ -n $output ]]; then
-          echo "ERROR: $output"
+          toCheck =
+            lib.optionalAttrs cfg.checkWarnings { inherit warnings; }
+            // lib.optionalAttrs cfg.checkAssertions { inherit assertions; };
+
+          errors = lib.foldlAttrs (
+            err: name: lines:
+            err + showErr name lines
+          ) "" toCheck;
+        in
+        lib.optionalString (errors != "") ''
+          echo -n ${lib.escapeShellArg errors}
           exit 1
-        fi
-      '';
+        ''
+        # We need to set HOME because neovim will try to create some files
+        #
+        # Because neovim does not return an exitcode when quitting we need to check if there are
+        # errors on stderr
+        + lib.optionalString cfg.runNvim ''
+          mkdir -p .cache/nvim
+
+          output=$(HOME=$(realpath .) nvim -mn --headless "+q" 2>&1 >/dev/null)
+          if [[ -n $output ]]; then
+            echo "ERROR: $output"
+            exit 1
+          fi
+        '';
 
       # If we don't do this nix is not happy
       installPhase = ''