[libcalamares] Refactor data-loading in Settings

- expose, for testing purposes, the load-from-YAML-data part
  alongside the public constructor that reads a YAML file
- add test for building the list of instances

src/libcalamares/Settings.cpp

@@ -213,6 +213,16 @@ interpretSequence( const YAML::Node& node, Settings::ModuleSequence& moduleSeque
     }
 }
 
+Settings::Settings( bool debugMode )
+    : QObject()
+    , m_debug( debugMode )
+    , m_doChroot( true )
+    , m_promptInstall( false )
+    , m_disableCancel( false )
+    , m_disableCancelDuringExec( false )
+{
+}
+
 Settings::Settings( const QString& settingsFilePath, bool debugMode )
     : QObject()
     , m_debug( debugMode )
@@ -225,15 +235,26 @@ Settings::Settings( const QString& settingsFilePath, bool debugMode )
     QFile file( settingsFilePath );
     if ( file.exists() && file.open( QFile::ReadOnly | QFile::Text ) )
     {
-        QByteArray ba = file.readAll();
+        setConfiguration( file.readAll(), file.fileName() );
+    }
+    else
+    {
+        cWarning() << "Cannot read settings file" << file.fileName();
+    }
 
+    s_instance = this;
+}
+
+void
+Settings::setConfiguration( const QByteArray& ba, const QString& explainName )
+{
     try
     {
         YAML::Node config = YAML::Load( ba.constData() );
         Q_ASSERT( config.IsMap() );
 
         interpretModulesSearch(
-                debugMode, CalamaresUtils::yamlToStringList( config[ "modules-search" ] ), m_modulesSearchPaths );
+            debugMode(), CalamaresUtils::yamlToStringList( config[ "modules-search" ] ), m_modulesSearchPaths );
         interpretInstances( config[ "instances" ], m_customModuleInstances );
         interpretSequence( config[ "sequence" ], m_modulesSequence );
 
@@ -247,17 +268,9 @@ Settings::Settings( const QString& settingsFilePath, bool debugMode )
     }
     catch ( YAML::Exception& e )
     {
-            CalamaresUtils::explainYamlException( e, ba, file.fileName() );
+        CalamaresUtils::explainYamlException( e, ba, explainName );
     }
 }
-    else
-    {
-        cWarning() << "Cannot read settings file" << file.fileName();
-    }
-
-    s_instance = this;
-}
-
 
 QStringList
 Settings::modulesSearchPaths() const

src/libcalamares/Settings.h

@@ -77,8 +77,14 @@ private:
 class DLLEXPORT Settings : public QObject
 {
     Q_OBJECT
+#ifdef BUILD_AS_TEST
+public:
+#endif
+    explicit Settings( bool debugMode );
     explicit Settings( const QString& settingsFilePath, bool debugMode );
 
+    void setConfiguration( const QByteArray& configData, const QString& explainName );
+
 public:
     static Settings* instance();
     /// @brief Find a settings.conf, following @p debugMode

src/libcalamares/Tests.cpp

@@ -44,6 +44,8 @@ private Q_SLOTS:
 
     void testInstanceKey();
     void testInstanceDescription();
+
+    void testSettings();
 };
 
 void
@@ -374,6 +376,75 @@ TestLibCalamares::testInstanceDescription()
     }
 }
 
+void
+TestLibCalamares::testSettings()
+{
+    {
+        Calamares::Settings s( false );
+        QVERIFY( !s.debugMode() );
+    }
+    {
+        Calamares::Settings s( true );
+        QVERIFY( s.debugMode() );
+        QVERIFY( s.customModuleInstances().isEmpty() );
+        QVERIFY( s.modulesSequence().isEmpty() );
+        QVERIFY( s.brandingComponentName().isEmpty() );
+
+        s.setConfiguration( R"(---
+instances:
+    - module: welcome
+      id: hi
+      weight: 75
+    - module: welcome
+      id: yo
+      config: yolo.conf
+sequence:
+    - show:
+        - welcome@hi
+        - welcome@yo
+        - dummycpp
+        - summary
+    - exec:
+        - welcome@hi
+)",
+                            QStringLiteral( "<testdata>" ) );
+
+        QVERIFY( s.debugMode() );
+        QCOMPARE( s.customModuleInstances().count(), 2 );
+        QCOMPARE( s.modulesSequence().count(), 2 );  // 2 steps (show, exec)
+        QVERIFY( s.brandingComponentName().isEmpty() );
+
+        // Make a lambda where we can adjust what it looks for from the outside,
+        //   by capturing a reference.
+        QString moduleKey = QString( "welcome" );
+        auto moduleFinder = [&moduleKey]( const Calamares::InstanceDescription& d ) {
+            return d.isValid() && d.key().module() == moduleKey;
+        };
+
+        const auto it0 = std::find_if(
+            s.customModuleInstances().constBegin(), s.customModuleInstances().constEnd(), moduleFinder );
+        QVERIFY( it0 != s.customModuleInstances().constEnd() );
+
+        moduleKey = QString( "derp" );
+        const auto it1 = std::find_if(
+            s.customModuleInstances().constBegin(), s.customModuleInstances().constEnd(), moduleFinder );
+        QVERIFY( it1 == s.customModuleInstances().constEnd() );
+
+        int validCount = 0;
+        int customCount = 0;
+        for ( const auto& d : s.customModuleInstances() )
+        {
+            if ( d.isValid() )
+                validCount++;
+            if ( d.isCustom() )
+                customCount++;
+            QVERIFY( d.isCustom() ? d.isValid() : true );  // All custom entries are valid
+        }
+        QCOMPARE( customCount, 2 );
+        QCOMPARE( validCount, 2 );
+    }
+}
+
 
 QTEST_GUILESS_MAIN( TestLibCalamares )