tst_QStringBuilder: add more checks

- for const char[] with embedded NULs
  - incl consistency between QString and QByteArray targets
    (inconsistent, filed as QTBUG-117321)

- with QByteArrayView as LHS

Task-number: QTBUG-117321
Pick-to: 6.7 6.5 6.2
Change-Id: Ieef9a4cf917f737da53112f89a1d95c97ebade06
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit 57a65735f25774d39214e2199916e9801ac69dd6)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

tests/auto/corelib/text/qstringbuilder/qstringbuilder1/stringbuilder.cpp

@@ -377,6 +377,8 @@ void runScenario()
     char chararray[3] = { 'H', 'i', '\0' };
     const char constchararray[3] = { 'H', 'i', '\0' };
     char achar = 'a';
+    char embedded_NULs[16] = { 'H', 'i' };
+    const char const_embedded_NULs[16] = { 'H', 'i' };
 
     CHECK(P, bytearray, bytearray);
     CHECK(P, QByteArray(bytearray), bytearray);
@@ -400,6 +402,33 @@ void runScenario()
     CHECK(P, bytearray, achar);
     CHECK(Q, bytearray, constchararray);
     CHECK(Q, bytearray, achar);
+    CHECK(Q, bytearray, embedded_NULs);
+    CHECK(Q, bytearray, const_embedded_NULs);
+
+    CHECK(Q, baview, bytearray);
+    CHECK(Q, baview, charstar);
+    CHECK(Q, baview, chararray);
+    CHECK(Q, baview, constchararray);
+    CHECK(Q, baview, achar);
+    CHECK(Q, baview, embedded_NULs);
+    CHECK(Q, baview, const_embedded_NULs);
+
+    // Check QString/QByteArray consistency when appending const char[] with embedded NULs:
+    {
+        const QByteArray ba = baview Q embedded_NULs;
+        QEXPECT_FAIL("", "QTBUG-117321", Continue);
+        QCOMPARE(ba.size(), baview.size() + q20::ssize(embedded_NULs) - 1);
+
+#ifndef QT_NO_CAST_FROM_ASCII
+        const auto l1s = QLatin1StringView{baview}; // l1string != baview
+
+        const QString s = l1s Q embedded_NULs;
+        QCOMPARE(s.size(), l1s.size() + q20::ssize(embedded_NULs) - 1);
+
+        QEXPECT_FAIL("", "QTBUG-117321", Continue);
+        QCOMPARE(s, ba);
+#endif
+    }
 
     //CHECK(Q, charstar, charstar);     // BUILTIN <-> BUILTIN cat't be overloaded
     //CHECK(Q, charstar, chararray);

tests/auto/corelib/text/qstringbuilder/qstringbuilder1/tst_qstringbuilder1.cpp

@@ -15,6 +15,8 @@
 #include <QtCore/QStringBuilder>
 #include <QtTest/QTest>
 
+#include <QtCore/q20iterator.h>
+
 #define LITERAL "some literal"
 
 namespace {

tests/auto/corelib/text/qstringbuilder/qstringbuilder2/tst_qstringbuilder2.cpp

@@ -16,6 +16,8 @@
 #include <QtCore/QStringBuilder>
 #include <QtTest/QTest>
 
+#include <QtCore/q20iterator.h>
+
 #define LITERAL "some literal"
 
 namespace {

tests/auto/corelib/text/qstringbuilder/qstringbuilder3/tst_qstringbuilder3.cpp

@@ -15,6 +15,8 @@
 #include <QtCore/QStringBuilder>
 #include <QtTest/QTest>
 
+#include <QtCore/q20iterator.h>
+
 #define LITERAL "some literal"
 
 namespace {

tests/auto/corelib/text/qstringbuilder/qstringbuilder4/tst_qstringbuilder4.cpp

@@ -16,6 +16,8 @@
 #include <QtCore/QStringBuilder>
 #include <QtTest/QTest>
 
+#include <QtCore/q20iterator.h>
+
 #define LITERAL "some literal"
 
 namespace {