nixos/testing: Fix release.nix tests evaluation

Fixes the problem introduced by 12b3066aae46a8ccc3d21f54f668a3f4be344332
which caused nixos/release.nix to return the wrong attributes, while
intending to only affect nixos/lib's runTest.
This also removes callTest from the test options, because callTest is
only ever invoked by all-tests.nix.

nixos/lib/testing-python.nix

···
     , extraPythonPackages ? (_ : [])
     , interactive ? {}
     } @ t:
-      runTest {
+      (evalTest {
         imports = [
           { _file = "makeTest parameters"; config = t; }
           {
···
             };
           }
         ];
-      };
+      }).config;
 
   simpleTest = as: (makeTest as).test;
 

nixos/lib/testing/call-test.nix

···
 in
 {
   options = {
-    callTest = mkOption {
-      internal = true;
-      type = types.functionTo types.raw;
-    };
     result = mkOption {
       internal = true;
-      default = config.test;
+      default = config;
     };
   };
 }

nixos/lib/testing/default.nix

···
 let
 
   evalTest = module: lib.evalModules { modules = testModules ++ [ module ]; };
-  runTest = module: (evalTest module).config.result;
+  runTest = module: (evalTest ({ config, ... }: { imports = [ module ]; result = config.test; })).config.result;
 
   testModules = [
     ./call-test.nix

nixos/tests/all-tests.nix

···
 
   inherit
     (rec {
-      doRunTest = arg: (import ../lib/testing-python.nix { inherit system pkgs; }).runTest {
-        imports = [ arg { inherit callTest; } ];
-      };
+      doRunTest = arg: ((import ../lib/testing-python.nix { inherit system pkgs; }).evalTest {
+        imports = [ arg ];
+      }).config.result;
       findTests = tree:
         if tree?recurseForDerivations && tree.recurseForDerivations
         then

pkgs/build-support/testers/default.nix

···
             else test;
           calledTest = lib.toFunction loadedTest pkgs;
         in
-          nixosTesting.makeTest calledTest;
+          nixosTesting.simpleTest calledTest;
 
 }