DebugTools: properly skip CompareImage tests with converters missing.

It only checked for importers, but the second part of these tests uses
also image converters to produce the actual files.

src/Magnum/DebugTools/Test/CompareImageTest.cpp

@@ -1095,6 +1095,10 @@ void CompareImageTest::imageFileError() {
     if(Utility::Directory::exists(filename))
         CORRADE_VERIFY(Utility::Directory::rm(filename));
 
+    if(!(_converterManager->loadState("AnyImageConverter") & PluginManager::LoadState::Loaded) ||
+       !(_converterManager->loadState("TgaImageConverter") & PluginManager::LoadState::Loaded))
+        CORRADE_SKIP("AnyImageConverter / TgaImageConverter plugins not found.");
+
     {
         out.str({});
         Debug redirectOutput(&out);
@@ -1180,6 +1184,10 @@ void CompareImageTest::imageFileExpectedLoadFailed() {
     if(Utility::Directory::exists(filename))
         CORRADE_VERIFY(Utility::Directory::rm(filename));
 
+    if(!(_converterManager->loadState("AnyImageConverter") & PluginManager::LoadState::Loaded) ||
+       !(_converterManager->loadState("TgaImageConverter") & PluginManager::LoadState::Loaded))
+        CORRADE_SKIP("AnyImageConverter / TgaImageConverter plugins not found.");
+
     {
         out.str({});
         Debug redirectOutput(&out);
@@ -1318,6 +1326,10 @@ void CompareImageTest::imageToFileError() {
     if(Utility::Directory::exists(filename))
         CORRADE_VERIFY(Utility::Directory::rm(filename));
 
+    if(!(_converterManager->loadState("AnyImageConverter") & PluginManager::LoadState::Loaded) ||
+       !(_converterManager->loadState("TgaImageConverter") & PluginManager::LoadState::Loaded))
+        CORRADE_SKIP("AnyImageConverter / TgaImageConverter plugins not found.");
+
     {
         out.str({});
         Debug redirectOutput(&out);
@@ -1379,6 +1391,10 @@ void CompareImageTest::imageToFileExpectedLoadFailed() {
     if(Utility::Directory::exists(filename))
         CORRADE_VERIFY(Utility::Directory::rm(filename));
 
+    if(!(_converterManager->loadState("AnyImageConverter") & PluginManager::LoadState::Loaded) ||
+       !(_converterManager->loadState("TgaImageConverter") & PluginManager::LoadState::Loaded))
+        CORRADE_SKIP("AnyImageConverter / TgaImageConverter plugins not found.");
+
     {
         out.str({});
         Debug redirectOutput(&out);
@@ -1674,6 +1690,10 @@ void CompareImageTest::pixelsToFileError() {
     if(Utility::Directory::exists(filename))
         CORRADE_VERIFY(Utility::Directory::rm(filename));
 
+    if(!(_converterManager->loadState("AnyImageConverter") & PluginManager::LoadState::Loaded) ||
+       !(_converterManager->loadState("TgaImageConverter") & PluginManager::LoadState::Loaded))
+        CORRADE_SKIP("AnyImageConverter / TgaImageConverter plugins not found.");
+
     {
         out.str({});
         Debug redirectOutput(&out);