diff --git a/java/execution/impl/src/com/intellij/execution/testDiscovery/TestDiscoveryConfigurationProducer.java b/java/execution/impl/src/com/intellij/execution/testDiscovery/TestDiscoveryConfigurationProducer.java
index 821b00a86b5b..0fb16e69a8ea 100644
--- a/java/execution/impl/src/com/intellij/execution/testDiscovery/TestDiscoveryConfigurationProducer.java
+++ b/java/execution/impl/src/com/intellij/execution/testDiscovery/TestDiscoveryConfigurationProducer.java
@@ -141,7 +141,7 @@ public abstract class TestDiscoveryConfigurationProducer extends JavaRunConfigur
     };
   }
 
-  public static Module detectTargetModule(List<Module> survivedModules, Project project) {
+  public static Module detectTargetModule(Collection<Module> survivedModules, Project project) {
     ModuleManager moduleManager = ModuleManager.getInstance(project);
     final Set<Module> allModules = new HashSet<>(Arrays.asList(moduleManager.getModules()));
     survivedModules
diff --git a/java/execution/impl/src/com/intellij/execution/testDiscovery/actions/DiscoveredTestsTree.java b/java/execution/impl/src/com/intellij/execution/testDiscovery/actions/DiscoveredTestsTree.java
index 4feb44d28360..33e3e5fc265d 100644
--- a/java/execution/impl/src/com/intellij/execution/testDiscovery/actions/DiscoveredTestsTree.java
+++ b/java/execution/impl/src/com/intellij/execution/testDiscovery/actions/DiscoveredTestsTree.java
@@ -35,6 +35,7 @@ import javax.swing.tree.TreeModel;
 import javax.swing.tree.TreePath;
 import javax.swing.tree.TreeSelectionModel;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 class DiscoveredTestsTree extends Tree implements DataProvider {
@@ -97,11 +98,12 @@ class DiscoveredTestsTree extends Tree implements DataProvider {
     myModel.addTest(testClass, testMethod);
   }
 
-  public List<Module> getContainingModules() {
+  @NotNull
+  public Set<Module> getContainingModules() {
     return myModel.getTestClasses().stream()
                   .map(element -> ModuleUtilCore.findModuleForPsiElement(element))
                   .filter(module -> module != null)
-                  .collect(Collectors.toList());
+                  .collect(Collectors.toSet());
   }
 
   public PsiMethod[] getTestMethods() {