From 0f967e03461b6d37c2218ba555cf23733648906c Mon Sep 17 00:00:00 2001
From: Tim Ebbeke <Tim06TR@gmail.com>
Date: Wed, 31 May 2023 00:54:27 +0200
Subject: [PATCH] Added more stabilize tests.

---
 .../nui/frontend/utility/stabilize.hpp        |  5 +-
 nui/src/nui/frontend/utility/stabilize.cpp    |  5 ++
 nui/test/nui/test_render.hpp                  | 67 +++++++++++++++++--
 3 files changed, 69 insertions(+), 8 deletions(-)

diff --git a/nui/include/nui/frontend/utility/stabilize.hpp b/nui/include/nui/frontend/utility/stabilize.hpp
index 38fcb6f..def2fe0 100644
--- a/nui/include/nui/frontend/utility/stabilize.hpp
+++ b/nui/include/nui/frontend/utility/stabilize.hpp
@@ -16,10 +16,7 @@ namespace Nui
         {}
 
         /// Resets the stable element, so that it is re-rendered on the next render.
-        void reset()
-        {
-            stableElement_ = {};
-        }
+        void reset();
 
         friend ElementRenderer stabilize(StableElement& stableElement, ElementRenderer const& encapsulatedRenderer);
 
diff --git a/nui/src/nui/frontend/utility/stabilize.cpp b/nui/src/nui/frontend/utility/stabilize.cpp
index f20622e..5098a80 100644
--- a/nui/src/nui/frontend/utility/stabilize.cpp
+++ b/nui/src/nui/frontend/utility/stabilize.cpp
@@ -5,6 +5,11 @@
 
 namespace Nui
 {
+    void StableElement::reset()
+    {
+        stableElement_ = {};
+    }
+
     ElementRenderer stabilize(StableElement& stableElement, ElementRenderer const& encapsulatedRenderer)
     {
         return [encapsulatedRenderer,
diff --git a/nui/test/nui/test_render.hpp b/nui/test/nui/test_render.hpp
index 5c68e87..2029012 100644
--- a/nui/test/nui/test_render.hpp
+++ b/nui/test/nui/test_render.hpp
@@ -322,12 +322,13 @@ namespace Nui::Tests
                 {
                     static std::string once = "once";
                     static std::string onceClass = "onceClass";
-                    return stabilize(
-                        stable, 
+                    const auto s = stabilize(
+                        stable,
                         span{id = once}(button{class_ = onceClass}())
                     );
                     once = "X";
                     onceClass = "Y";
+                    return s;
                 }
             }
         ));
@@ -376,7 +377,7 @@ namespace Nui::Tests
                 else
                 {
                     return stabilize(
-                        stable, 
+                        stable,
                         span{id = spanId}()
                     );
                 }
@@ -426,7 +427,7 @@ namespace Nui::Tests
                 else
                 {
                     return stabilize(
-                        stable, 
+                        stable,
                         // fragment is ignored and forms a div, because StableElements can only be one element
                         fragment(a{}(), span{}())
                     );
@@ -458,4 +459,62 @@ namespace Nui::Tests
         ASSERT_EQ(Nui::val::global("document")["body"]["children"]["length"].as<long long>(), 1);
         EXPECT_EQ(Nui::val::global("document")["body"]["children"][0]["tagName"].as<std::string>(), "div");
     }
+
+    TEST_F(TestRender, CanResetStableElement)
+    {
+        using Nui::Elements::div;
+        using Nui::Elements::span;
+        using Nui::Elements::button;
+        using namespace Nui::Attributes;
+
+        Nui::Observed<bool> toggle = true;
+        StableElement stable;
+
+        std::string once = "once";
+        std::string onceClass = "onceClass";
+
+        // clang-format off
+        render(div{}(
+            observe(toggle),
+            [&toggle, &stable, &once, &onceClass]() -> Nui::ElementRenderer{
+                if (!*toggle)
+                    return nil();
+                else
+                {
+                    const auto s = stabilize(
+                        stable, 
+                        span{id = once}(button{class_ = onceClass}())
+                    );
+                    once = "X";
+                    onceClass = "Y";
+                    return s;
+                }
+            }
+        ));
+        // clang-format on
+
+        ASSERT_EQ(Nui::val::global("document")["body"]["children"]["length"].as<long long>(), 1);
+        EXPECT_EQ(Nui::val::global("document")["body"]["children"][0]["tagName"].as<std::string>(), "span");
+        EXPECT_EQ(Nui::val::global("document")["body"]["children"][0]["attributes"]["id"].as<std::string>(), "once");
+        EXPECT_EQ(
+            Nui::val::global("document")["body"]["children"][0]["children"][0]["tagName"].as<std::string>(), "button");
+        EXPECT_EQ(
+            Nui::val::global("document")["body"]["children"][0]["children"][0]["attributes"]["class"].as<std::string>(),
+            "onceClass");
+
+        toggle = false;
+        globalEventContext.executeActiveEventsImmediately();
+
+        stable.reset();
+
+        toggle = true;
+        globalEventContext.executeActiveEventsImmediately();
+
+        ASSERT_EQ(Nui::val::global("document")["body"]["children"]["length"].as<long long>(), 1);
+        EXPECT_EQ(Nui::val::global("document")["body"]["children"][0]["tagName"].as<std::string>(), "span");
+        EXPECT_EQ(Nui::val::global("document")["body"]["children"][0]["attributes"]["id"].as<std::string>(), "X");
+        EXPECT_EQ(
+            Nui::val::global("document")["body"]["children"][0]["children"][0]["attributes"]["class"].as<std::string>(),
+            "Y");
+    }
 }
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