[calamares] Add a test-application.

This test-application should load a single module and execute it --
that can be used to quickly test configurations, loading, etc. This
is preparation for loading all sorts of Python modules by PythonQt.

The loader does some internals initialization and gets the module,
but doesn't actually run it yet.

src/calamares/CMakeLists.txt

@@ -68,3 +68,9 @@ install( FILES ${CMAKE_SOURCE_DIR}/data/images/squid.svg
     RENAME calamares.svg
     DESTINATION ${CMAKE_INSTALL_DATADIR}/icons/hicolor/scalable/apps
 )
+
+if( BUILD_TESTING )
+    add_executable( loadmodule testmain.cpp )
+    target_link_libraries( loadmodule ${CALAMARES_LIBRARIES} Qt5::Core Qt5::Widgets calamaresui )
+    # Don't install, it's just for enable_testing
+endif()

src/calamares/testmain.cpp

@@ -0,0 +1,153 @@
+/* === This file is part of Calamares - <https://github.com/calamares> ===
+ *
+ *   Copyright 2018, 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
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This executable loads and runs a Calamares Python module
+ * within a C++ application, in order to test the different
+ * bindings.
+ */
+
+#include "utils/Logger.h"
+#include "utils/YamlUtils.h"
+#include "modulesystem/Module.h"
+
+#include "Settings.h"
+
+#include <QCommandLineOption>
+#include <QCommandLineParser>
+#include <QCoreApplication>
+#include <QFileInfo>
+
+#include <memory>
+
+static QString
+handle_args( QCoreApplication& a )
+{
+    QCommandLineOption debugLevelOption( QStringLiteral("D"),
+                                          "Verbose output for debugging purposes (0-8).", "level" );
+
+    QCommandLineParser parser;
+    parser.setApplicationDescription( "Calamares module tester" );
+    parser.addHelpOption();
+    parser.addVersionOption();
+
+    parser.addOption( debugLevelOption );
+    parser.addPositionalArgument( "module", "Path or name of module to run." );
+
+    parser.process( a );
+
+    if ( parser.isSet( debugLevelOption ) )
+    {
+        bool ok = true;
+        int l = parser.value( debugLevelOption ).toInt( &ok );
+        unsigned int dlevel = 0;
+        if ( !ok || ( l < 0 ) )
+            dlevel = Logger::LOGVERBOSE;
+        else
+            dlevel = l;
+        Logger::setupLogLevel( dlevel );
+    }
+
+    const QStringList args = parser.positionalArguments();
+    if ( args.isEmpty() )
+    {
+        cError() << "Missing <module> path.\n";
+        parser.showHelp();
+        return QString();  // NOTREACHED
+    }
+    if ( args.size() > 1 )
+    {
+        cError() << "More than one <module> path.\n";
+        parser.showHelp();
+        return QString();  // NOTREACHED
+    }
+
+    return args.first();
+}
+
+
+static Calamares::Module*
+load_module( const QString& moduleName )
+{
+    QFileInfo fi;
+
+    bool ok = false;
+    QVariantMap descriptor;
+
+    for ( const QString& prefix : QStringList{ "./", "src/modules/", "modules/" } )
+    {
+        // Could be a complete path, eg. src/modules/dummycpp/module.desc
+        fi = QFileInfo( prefix + moduleName );
+        if ( fi.exists() && fi.isFile() )
+            descriptor = CalamaresUtils::loadYaml( fi, &ok );
+        if ( ok )
+            break;
+
+        // Could be a path without module.desc
+        fi = QFileInfo( prefix + moduleName );
+        if ( fi.exists() && fi.isDir() )
+        {
+            fi = QFileInfo( prefix + moduleName + "/module.desc" );
+            if ( fi.exists() && fi.isFile() )
+                descriptor = CalamaresUtils::loadYaml( fi, &ok );
+            if ( ok ) break;
+        }
+    }
+
+    if ( !ok )
+    {
+        cWarning() << "No suitable module descriptor found.";
+        return nullptr;
+    }
+
+    QString name = descriptor.value( "name" ).toString();
+    if ( name.isEmpty() )
+    {
+        cWarning() << "No name found in module descriptor" << fi.absoluteFilePath();
+        return nullptr;
+    }
+
+    QString moduleDirectory = fi.absolutePath();
+    QString configFile = moduleDirectory + '/' + name + ".conf";
+
+    Calamares::Module* module = Calamares::Module::fromDescriptor(
+        descriptor, name, configFile, moduleDirectory );
+
+    return module;
+}
+
+int
+main( int argc, char* argv[] )
+{
+    QCoreApplication a( argc, argv );
+
+    QString module = handle_args( a );
+    if ( module.isEmpty() )
+        return 1;
+
+    std::unique_ptr< Calamares::Settings > settings_p( new Calamares::Settings( QString(), true ) );
+    cDebug() << "Calamares test module-loader" << module;
+    Calamares::Module* m = load_module( module );
+    if ( !m )
+    {
+        cError() << "No module.desc data found in" << module;
+        return 1;
+    }
+
+    return 0;
+}