diff --git a/modules/juce_gui_basics/components/juce_FocusTraverser.cpp b/modules/juce_gui_basics/components/juce_FocusTraverser.cpp
index 6dfa92f831..6290f7dbd6 100644
--- a/modules/juce_gui_basics/components/juce_FocusTraverser.cpp
+++ b/modules/juce_gui_basics/components/juce_FocusTraverser.cpp
@@ -172,6 +172,7 @@ struct FocusTraverserTests  : public UnitTest
     void runTest() override
     {
         ScopedJuceInitialiser_GUI libraryInitialiser;
+        const MessageManagerLock mml;
 
         beginTest ("Basic traversal");
         {
diff --git a/modules/juce_gui_basics/keyboard/juce_KeyboardFocusTraverser.cpp b/modules/juce_gui_basics/keyboard/juce_KeyboardFocusTraverser.cpp
index a59585429f..aabcca90c4 100644
--- a/modules/juce_gui_basics/keyboard/juce_KeyboardFocusTraverser.cpp
+++ b/modules/juce_gui_basics/keyboard/juce_KeyboardFocusTraverser.cpp
@@ -103,6 +103,7 @@ struct KeyboardFocusTraverserTests  : public UnitTest
     void runTest() override
     {
         ScopedJuceInitialiser_GUI libraryInitialiser;
+        const MessageManagerLock mml;
 
         beginTest ("No child wants keyboard focus");
         {