Add test for pluginWrapper with fn input and tests for lazyPluginClosure.

tests/lazyUtils.nix

@@ -120,6 +120,10 @@ in
           dir = miniDrv;
         };
       };
+      testFn = {
+        expr = (lazyUtils.helpers.pluginWrapper (_: "test")).dir null;
+        expected = "test";
+      };
       testSet = {
         expr = lazyUtils.helpers.pluginWrapper { };
         expected = { };
@@ -130,4 +134,14 @@ in
       };
     };
   };
+  lazyPluginClosure = {
+    testShort = {
+      expr = lazyUtils.lazyPluginClosure "pluginName";
+      expected = ''{"pluginName",name = "pluginName"}'';
+    };
+    testDrv = {
+      expr = lazyUtils.lazyPluginClosure miniDrv;
+      expected = ''{dir = "${miniDrv.outPath}",name = "${miniDrv.name}"}'';
+    };
+  };
 }