[locale] Extend tests with tz-image-validation

- The idea is to check all the TZ images for consistency, like
  TimeZoneWidget::setCurrentLocation() does when DEBUG_TIMEZONES is
  on; a zone-pixel should be set in only **one** image.

The test so far is just a stub.

src/modules/locale/Tests.cpp

@@ -1,6 +1,6 @@
 /* === This file is part of Calamares - <http://github.com/calamares> ===
  *
- *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2019-2020, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -20,6 +20,8 @@
 #include "Tests.h"
 #include "LocaleConfiguration.h"
 
+#include "locale/TimeZone.h"
+
 #include <QtTest/QtTest>
 
 QTEST_GUILESS_MAIN( LocaleTests )
@@ -77,3 +79,20 @@ LocaleTests::testSplitLocaleConfiguration()
     QCOMPARE( lc3.toBcp47(), QStringLiteral( "da" ) );
     QCOMPARE( lc3.lc_numeric, QStringLiteral( "de_DE.UTF-8" ) );
 }
+
+void
+LocaleTests::testTZImages()
+{
+    Logger::setupLogLevel( Logger::LOGDEBUG );
+    using namespace CalamaresUtils::Locale;
+    const CStringPairList& regions = TZRegion::fromZoneTab();
+
+    for ( const auto* pr : regions )
+    {
+        const TZRegion* region = dynamic_cast< const TZRegion* >( pr );
+        if ( region )
+        {
+            cDebug() << "Region" << region->region() << "zones #" << region->zones().count();
+        }
+    }
+}

src/modules/locale/Tests.h

@@ -1,6 +1,6 @@
 /* === This file is part of Calamares - <http://github.com/calamares> ===
  *
- *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2019-2020, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -35,6 +35,9 @@ private Q_SLOTS:
     void testEmptyLocaleConfiguration();
     void testDefaultLocaleConfiguration();
     void testSplitLocaleConfiguration();
+
+    // Check the TZ images for consistency
+    void testTZImages();
 };
 
 #endif