Add mixed consumption patterns test

Test that the same value group can be consumed as both map and slice
in different parts of the same application. This validates an important
real-world use case where hybrid consumption patterns are needed.

Author: jquirke

map_groups_test.go

@@ -468,5 +468,60 @@ func TestMapValueGroupsEdgeCases(t *testing.T) {
 		require.Error(t, err)
 		assert.Contains(t, err.Error(), "value groups may be consumed as slices or string-keyed maps only")
 	})
+
+	t.Run("mixed consumption patterns", func(t *testing.T) {
+		t.Parallel()
+
+		var mapServices map[string]testSimpleService
+		var sliceServices []testSimpleService
+
+		app := fxtest.New(t,
+			fx.Provide(
+				// Named services for map consumption
+				fx.Annotate(
+					func() testSimpleService { return &testBasicService{name: "auth-service"} },
+					fx.ResultTags(`name:"auth" group:"services"`),
+				),
+				fx.Annotate(
+					func() testSimpleService { return &testBasicService{name: "billing-service"} },
+					fx.ResultTags(`name:"billing" group:"services"`),
+				),
+				fx.Annotate(
+					func() testSimpleService { return &testBasicService{name: "metrics-service"} },
+					fx.ResultTags(`name:"metrics" group:"services"`),
+				),
+			),
+			fx.Invoke(fx.Annotate(
+				func(services map[string]testSimpleService) {
+					mapServices = services
+				},
+				fx.ParamTags(`group:"services"`),
+			)),
+			fx.Invoke(fx.Annotate(
+				func(services []testSimpleService) {
+					sliceServices = services
+				},
+				fx.ParamTags(`group:"services"`),
+			)),
+		)
+		defer app.RequireStart().RequireStop()
+
+		// Map consumption should work with named services
+		require.Len(t, mapServices, 3)
+		require.Contains(t, mapServices, "auth")
+		require.Contains(t, mapServices, "billing")
+		require.Contains(t, mapServices, "metrics")
+		assert.Equal(t, "auth-service", mapServices["auth"].GetName())
+		assert.Equal(t, "billing-service", mapServices["billing"].GetName())
+		assert.Equal(t, "metrics-service", mapServices["metrics"].GetName())
+
+		// Slice consumption should also work with the same services
+		require.Len(t, sliceServices, 3)
+		serviceNames := make([]string, len(sliceServices))
+		for i, service := range sliceServices {
+			serviceNames[i] = service.GetName()
+		}
+		assert.ElementsMatch(t, []string{"auth-service", "billing-service", "metrics-service"}, serviceNames)
+	})
 }