Fixed some incorrect documentation in ValueWithDefault and added some unit tests to the class

modules/juce_data_structures/juce_data_structures.cpp

@@ -39,6 +39,7 @@
 #include "values/juce_ValueTree.cpp"
 #include "values/juce_ValueTreeSynchroniser.cpp"
 #include "values/juce_CachedValue.cpp"
+#include "values/juce_ValueWithDefault.cpp"
 #include "undomanager/juce_UndoManager.cpp"
 #include "app_properties/juce_ApplicationProperties.cpp"
 #include "app_properties/juce_PropertiesFile.cpp"

modules/juce_data_structures/values/juce_ValueWithDefault.cpp

@@ -0,0 +1,112 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE library.
+   Copyright (c) 2017 - ROLI Ltd.
+
+   JUCE is an open source library subject to commercial or open-source
+   licensing.
+
+   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
+   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
+   27th April 2017).
+
+   End User License Agreement: www.juce.com/juce-5-licence
+   Privacy Policy: www.juce.com/juce-5-privacy-policy
+
+   Or: You may also use this code under the terms of the GPL v3 (see
+   www.gnu.org/licenses).
+
+   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+namespace juce
+{
+
+#if JUCE_UNIT_TESTS
+
+class ValueWithDefaultTests  : public UnitTest
+{
+public:
+    ValueWithDefaultTests() : UnitTest ("ValueWithDefault", "Values") {}
+
+    void runTest() override
+    {
+        beginTest ("default constructor");
+        {
+            ValueWithDefault vwd;
+            expect (vwd.isUsingDefault());
+            expect (vwd.get() == var());
+        }
+
+        beginTest ("missing property");
+        {
+            ValueTree t ("root");
+            ValueWithDefault vwd (t, "testKey", nullptr, "default");
+
+            expect (vwd.isUsingDefault());
+            expectEquals (vwd.get().toString(), String ("default"));
+        }
+
+        beginTest ("empty property");
+        {
+            ValueTree t ("root");
+            t.setProperty ("testKey", {}, nullptr);
+
+            ValueWithDefault vwd (t, "testKey", nullptr, "default");
+
+            expect (vwd.isUsingDefault());
+            expectEquals (vwd.get().toString(), String ("default"));
+        }
+
+        beginTest ("non-empty property");
+        {
+            ValueTree t ("root");
+            t.setProperty ("testKey", "non-default", nullptr);
+
+            ValueWithDefault vwd (t, "testKey", nullptr, "default");
+
+            expect (! vwd.isUsingDefault());
+            expectEquals (vwd.get().toString(), String ("non-default"));
+        }
+
+        beginTest ("set default");
+        {
+            ValueTree t ("root");
+            t.setProperty ("testkey", {}, nullptr);
+
+            ValueWithDefault vwd (t, "testkey", nullptr);
+            vwd.setDefault ("default");
+
+            expect (vwd.isUsingDefault());
+            expectEquals (vwd.get().toString(), String ("default"));
+        }
+
+        beginTest ("set value");
+        {
+            ValueTree t ("root");
+            t.setProperty ("testkey", "testvalue", nullptr);
+
+            ValueWithDefault vwd (t, "testkey", nullptr, "default");
+            vwd = "newvalue";
+
+            expect (! vwd.isUsingDefault());
+            expectEquals (t["testkey"].toString(), String ("newvalue"));
+
+            vwd.resetToDefault();
+
+            expect (vwd.isUsingDefault());
+            expect (t["testkey"] == var());
+        }
+    }
+};
+
+static ValueWithDefaultTests valueWithDefaultTests;
+
+#endif
+
+} // namespace juce

modules/juce_data_structures/values/juce_ValueWithDefault.h

@@ -124,10 +124,10 @@ public:
     /** Returns true if the property does not exist or is empty. */
     bool isUsingDefault() const
     {
-        return ! targetTree.hasProperty (targetProperty);
+        return ! targetTree.hasProperty (targetProperty) || targetTree.getProperty (targetProperty) == var();
     }
 
-    /** Resets the property to an empty var. */
+    /** Removes the property from the referenced ValueTree. */
     void resetToDefault() noexcept
     {
         targetTree.removeProperty (targetProperty, nullptr);