From e602b22bfb3f8ec0af8eea0948c739d1960006d3 Mon Sep 17 00:00:00 2001
From: Valentin Shergin <shergin@fb.com>
Date: Mon, 16 Mar 2020 10:17:37 -0700
Subject: [PATCH] Fabric: Tests for `traitCast<>`

Summary:
Subject.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: sammy-SC

Differential Revision: D20462834

fbshipit-source-id: 13e3c3b45537e22002b948f967a2576bc52145e8
---
 ReactCommon/fabric/core/BUCK                  |   3 +
 .../fabric/core/tests/traitCastTest.cpp       | 105 ++++++++++++++++++
 ReactCommon/fabric/element/BUCK               |   1 +
 ReactCommon/fabric/element/testUtils.h        |   9 ++
 4 files changed, 118 insertions(+)
 create mode 100644 ReactCommon/fabric/core/tests/traitCastTest.cpp

diff --git a/ReactCommon/fabric/core/BUCK b/ReactCommon/fabric/core/BUCK
index 2bab70459c730c..7a1cd7884c1506 100644
--- a/ReactCommon/fabric/core/BUCK
+++ b/ReactCommon/fabric/core/BUCK
@@ -85,6 +85,9 @@ fb_xplat_cxx_test(
     deps = [
         "fbsource//xplat/folly:molly",
         "fbsource//xplat/js/react-native-github/ReactCommon/fabric/element:element",
+        react_native_xplat_target("fabric/components/view:view"),
+        react_native_xplat_target("fabric/components/scrollview:scrollview"),
+        react_native_xplat_target("fabric/components/text:text"),
         "fbsource//xplat/third-party/gmock:gtest",
         react_native_xplat_target("fabric/components/view:view"),
         ":core",
diff --git a/ReactCommon/fabric/core/tests/traitCastTest.cpp b/ReactCommon/fabric/core/tests/traitCastTest.cpp
new file mode 100644
index 00000000000000..49a2f64d47a21c
--- /dev/null
+++ b/ReactCommon/fabric/core/tests/traitCastTest.cpp
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+
+#include <react/components/scrollview/ScrollViewComponentDescriptor.h>
+#include <react/components/text/ParagraphComponentDescriptor.h>
+#include <react/components/text/RawTextComponentDescriptor.h>
+#include <react/components/text/TextComponentDescriptor.h>
+#include <react/components/view/ViewComponentDescriptor.h>
+
+#include <react/element/Element.h>
+#include <react/element/testUtils.h>
+
+using namespace facebook::react;
+
+TEST(traitCastTest, testOne) {
+  auto builder = simpleComponentBuilder();
+
+  auto viewShadowNode = std::shared_ptr<ViewShadowNode>{};
+  auto scrollViewShadowNode = std::shared_ptr<ScrollViewShadowNode>{};
+  auto paragraphShadowNode = std::shared_ptr<ParagraphShadowNode>{};
+  auto textShadowNode = std::shared_ptr<TextShadowNode>{};
+  auto rawTextShadowNode = std::shared_ptr<RawTextShadowNode>{};
+
+  // clang-format off
+  auto element =
+      Element<ScrollViewShadowNode>()
+        .reference(scrollViewShadowNode)
+        .children({
+          Element<ParagraphShadowNode>()
+            .reference(paragraphShadowNode)
+            .children({
+              Element<TextShadowNode>()
+                .reference(textShadowNode),
+              Element<RawTextShadowNode>()
+                .reference(rawTextShadowNode)
+            }),
+          Element<ViewShadowNode>()
+            .reference(viewShadowNode),
+        });
+  // clang-format on
+
+  auto rootShadowNode = builder.build(element);
+
+  // Casting `nullptr` returns `nullptrs`.
+  EXPECT_FALSE(traitCast<LayoutableShadowNode const *>(nullptr));
+  EXPECT_FALSE(traitCast<YogaLayoutableShadowNode const *>(nullptr));
+
+  // `ViewShadowNode` is `LayoutableShadowNode` and `YogaLayoutableShadowNode`.
+  EXPECT_TRUE(traitCast<LayoutableShadowNode const *>(viewShadowNode.get()));
+  EXPECT_TRUE(
+      traitCast<YogaLayoutableShadowNode const *>(viewShadowNode.get()));
+  EXPECT_NO_FATAL_FAILURE(
+      traitCast<LayoutableShadowNode const &>(*viewShadowNode));
+  EXPECT_NO_FATAL_FAILURE(
+      traitCast<YogaLayoutableShadowNode const &>(*viewShadowNode));
+
+  // `ScrollViewShadowNode` is `LayoutableShadowNode` and
+  // `YogaLayoutableShadowNode`.
+  EXPECT_TRUE(
+      traitCast<LayoutableShadowNode const *>(scrollViewShadowNode.get()));
+  EXPECT_TRUE(
+      traitCast<YogaLayoutableShadowNode const *>(scrollViewShadowNode.get()));
+  EXPECT_NO_FATAL_FAILURE(
+      traitCast<LayoutableShadowNode const &>(*scrollViewShadowNode));
+  EXPECT_NO_FATAL_FAILURE(
+      traitCast<YogaLayoutableShadowNode const &>(*scrollViewShadowNode));
+
+  // `ParagraphShadowNode` is `LayoutableShadowNode` and
+  // `YogaLayoutableShadowNode`.
+  EXPECT_TRUE(
+      traitCast<LayoutableShadowNode const *>(paragraphShadowNode.get()));
+  EXPECT_TRUE(
+      traitCast<YogaLayoutableShadowNode const *>(paragraphShadowNode.get()));
+  EXPECT_NO_FATAL_FAILURE(
+      traitCast<LayoutableShadowNode const &>(*paragraphShadowNode));
+  EXPECT_NO_FATAL_FAILURE(
+      traitCast<YogaLayoutableShadowNode const &>(*paragraphShadowNode));
+
+  // `TextShadowNode` is *not* `LayoutableShadowNode` nor
+  // `YogaLayoutableShadowNode`.
+  EXPECT_FALSE(traitCast<LayoutableShadowNode const *>(textShadowNode.get()));
+  EXPECT_FALSE(
+      traitCast<YogaLayoutableShadowNode const *>(textShadowNode.get()));
+  EXPECT_DEATH_IF_SUPPORTED(
+      traitCast<LayoutableShadowNode const &>(*textShadowNode), "");
+  EXPECT_DEATH_IF_SUPPORTED(
+      traitCast<YogaLayoutableShadowNode const &>(*textShadowNode), "");
+
+  // `RawTextShadowNode` is *not* `LayoutableShadowNode` nor
+  // `YogaLayoutableShadowNode`.
+  EXPECT_FALSE(
+      traitCast<LayoutableShadowNode const *>(rawTextShadowNode.get()));
+  EXPECT_FALSE(
+      traitCast<YogaLayoutableShadowNode const *>(rawTextShadowNode.get()));
+  EXPECT_DEATH_IF_SUPPORTED(
+      traitCast<LayoutableShadowNode const &>(*rawTextShadowNode), "");
+  EXPECT_DEATH_IF_SUPPORTED(
+      traitCast<YogaLayoutableShadowNode const &>(*rawTextShadowNode), "");
+}
diff --git a/ReactCommon/fabric/element/BUCK b/ReactCommon/fabric/element/BUCK
index db36226e8d7fec..d40596e59c4ec5 100644
--- a/ReactCommon/fabric/element/BUCK
+++ b/ReactCommon/fabric/element/BUCK
@@ -55,6 +55,7 @@ rn_xplat_cxx_library(
         react_native_xplat_target("fabric/components/root:root"),
         react_native_xplat_target("fabric/components/view:view"),
         react_native_xplat_target("fabric/components/scrollview:scrollview"),
+        react_native_xplat_target("fabric/components/text:text"),
         react_native_xplat_target("fabric/uimanager:uimanager"),
         react_native_xplat_target("fabric/core:core"),
         react_native_xplat_target("fabric/debug:debug"),
diff --git a/ReactCommon/fabric/element/testUtils.h b/ReactCommon/fabric/element/testUtils.h
index f600ab758e81f6..008786913c1b77 100644
--- a/ReactCommon/fabric/element/testUtils.h
+++ b/ReactCommon/fabric/element/testUtils.h
@@ -9,6 +9,9 @@
 
 #include <react/components/root/RootComponentDescriptor.h>
 #include <react/components/scrollview/ScrollViewComponentDescriptor.h>
+#include <react/components/text/ParagraphComponentDescriptor.h>
+#include <react/components/text/RawTextComponentDescriptor.h>
+#include <react/components/text/TextComponentDescriptor.h>
 #include <react/components/view/ViewComponentDescriptor.h>
 #include <react/element/ComponentBuilder.h>
 #include <react/uimanager/ComponentDescriptorProviderRegistry.h>
@@ -29,6 +32,12 @@ inline ComponentBuilder simpleComponentBuilder() {
       concreteComponentDescriptorProvider<ViewComponentDescriptor>());
   componentDescriptorProviderRegistry.add(
       concreteComponentDescriptorProvider<ScrollViewComponentDescriptor>());
+  componentDescriptorProviderRegistry.add(
+      concreteComponentDescriptorProvider<ParagraphComponentDescriptor>());
+  componentDescriptorProviderRegistry.add(
+      concreteComponentDescriptorProvider<TextComponentDescriptor>());
+  componentDescriptorProviderRegistry.add(
+      concreteComponentDescriptorProvider<RawTextComponentDescriptor>());
 
   return ComponentBuilder{componentDescriptorRegistry};
 }