From 6555c626300a69faff87b9df21788ece545b2f58 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Sat, 19 Oct 2024 10:23:55 +0200
Subject: [PATCH] tst_QChar: add comprehensive conversion tests

As usual, when making a change, we find out that test coverage was
poor. Add such tests for QChar ctors.

Amends (should have been a prequel commit of)
9ef4c123c39c642357c9e8530d59f32f220a7824.

Conflict resolution for 6.8:
- adjusted static_asserts to old QChar ctor overload set

Pick-to: 6.5 6.2 5.15
Change-Id: Idcd9ab816ef815ce4a85dba1f7e37201b64c2203
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit 69190a370d1e9f60c78f3096df62a61b6a5d1384)
---
 tests/auto/corelib/text/qchar/tst_qchar.cpp | 55 +++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/tests/auto/corelib/text/qchar/tst_qchar.cpp b/tests/auto/corelib/text/qchar/tst_qchar.cpp
index fae507f4c6d..3428988f858 100644
--- a/tests/auto/corelib/text/qchar/tst_qchar.cpp
+++ b/tests/auto/corelib/text/qchar/tst_qchar.cpp
@@ -6,6 +6,61 @@
 #include <qfile.h>
 #include <qstringlist.h>
 
+#include <type_traits>
+
+template <typename C>
+constexpr inline bool implicitly = std::is_convertible_v<C, QChar>;
+template <typename C>
+constexpr inline bool explicitly = std::is_constructible_v<QChar, C>;
+template <typename C>
+constexpr inline bool disabled = !explicitly<C>;
+
+//
+// Conversion from character types
+//
+static_assert(implicitly<char>);
+#ifdef __cpp_char8_t
+static_assert(explicitly<char8_t>); // via integer promotion
+#endif
+static_assert(implicitly<char16_t>);
+#ifdef Q_OS_WIN
+static_assert(implicitly<wchar_t>);
+#else
+static_assert(explicitly<wchar_t>);
+#endif
+static_assert(explicitly<char32_t>);
+
+//
+// Conversion from others
+//
+static_assert(explicitly<uchar>);
+static_assert(implicitly<short>);
+static_assert(implicitly<ushort>);
+static_assert(explicitly<int>);
+static_assert(explicitly<uint>);
+
+//
+// Disabled conversions (from Qt 6.9)
+//
+static_assert(explicitly<bool>); // via integer promotion
+static_assert(disabled<std::byte>);
+static_assert(explicitly<signed char>); // via integer promotion
+static_assert(disabled<long>);
+static_assert(disabled<long long>);
+static_assert(disabled<unsigned long>);
+static_assert(disabled<unsigned long long>);
+static_assert(explicitly<Qt::Key>); // via promotion to underlying_type_t
+enum E1 {};
+static_assert(explicitly<E1>);      // ditto
+enum class E2 {};
+static_assert(disabled<E2>);
+#ifndef Q_OS_QNX // ¯\_(ツ)_/¯
+enum E1C : char16_t {};
+static_assert(explicitly<E1C>);
+#endif
+enum class E2C : char16_t {};
+static_assert(disabled<E2C>);
+
 class tst_QChar : public QObject
 {
     Q_OBJECT