Test for FindUIHelper

platform/lang-impl/src/com/intellij/find/impl/FindPopupPanel.java

@@ -383,6 +383,7 @@ public class FindPopupPanel extends JBPanel implements FindUI, DataProvider {
       public void update(@NotNull AnActionEvent e) {
         super.update(e);
         e.getPresentation().setEnabled(myHelper.getModel().isOpenInNewTabEnabled());
+        e.getPresentation().setVisible(myHelper.getModel().isOpenInNewTabVisible());
       }
     });
     tabResultsContextGroup.setPopup(true);

platform/lang-impl/src/com/intellij/find/impl/FindUIHelper.java

@@ -177,9 +177,8 @@ public class FindUIHelper implements Disposable {
   }
 
   void setUseSeparateView(boolean separateView) {
-    if (myModel.isOpenInNewTabEnabled()) {
-      myModel.setOpenInNewTab(separateView);
-    }
+    if (!myModel.isOpenInNewTabEnabled()) throw new IllegalStateException("'Open in new Tab' is not enabled");
+    myModel.setOpenInNewTab(separateView);
     FindSettings.getInstance().setShowResultsInSeparateView(separateView);
   }
 

platform/lang-impl/testSources/com/intellij/find/impl/FindUIHelperTest.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2000-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.find.impl;
+
+import com.intellij.find.FindManager;
+import com.intellij.find.FindModel;
+import com.intellij.testFramework.LightPlatformTestCase;
+
+public class FindUIHelperTest extends LightPlatformTestCase {
+  private static final Runnable STUB = () -> {
+  };
+  
+  private FindUIHelper myHelper;
+  private FindManagerImpl myFindManager;
+
+  @Override
+  protected void setUp() throws Exception {
+    super.setUp();
+    myFindManager = ((FindManagerImpl)FindManager.getInstance(getProject()));
+    FindModel findModel = FindManager.getInstance(getProject()).getFindInProjectModel();
+    myHelper = new FindUIHelper(getProject(), findModel, STUB);
+  }
+
+  public void testBasic() {
+    assertFalse(myHelper.getModel().isOpenInNewTabEnabled());
+    boolean initialSeparateViewState = myHelper.isUseSeparateView();
+    try {
+      myHelper.setUseSeparateView(!initialSeparateViewState);
+      fail("There should be an exception");
+    }
+    catch (IllegalStateException e) {
+      //it's ok
+      myHelper.getModel().setOpenInNewTabEnabled(true);
+      myHelper.setUseSeparateView(!initialSeparateViewState);
+    }
+    assertNotSame(initialSeparateViewState, myHelper.isUseSeparateView());
+    myHelper.setUseSeparateView(initialSeparateViewState);
+    assertSame(initialSeparateViewState, myHelper.isUseSeparateView());
+
+    boolean initialSkipResultsWithOneUsage = myHelper.isSkipResultsWithOneUsage();
+    myHelper.setSkipResultsWithOneUsage(!initialSkipResultsWithOneUsage);
+    assertNotSame(initialSeparateViewState, myHelper.isSkipResultsWithOneUsage());
+    myHelper.setSkipResultsWithOneUsage(initialSkipResultsWithOneUsage);
+    assertSame(initialSeparateViewState, myHelper.isSkipResultsWithOneUsage());
+
+    myFindManager.changeGlobalSettings(myHelper.getModel());
+
+    FindModel findModel = FindManager.getInstance(getProject()).getFindInProjectModel();
+    myHelper = new FindUIHelper(getProject(), findModel, STUB);
+    assertSame(initialSeparateViewState, myHelper.isUseSeparateView());
+    assertSame(initialSeparateViewState, myHelper.isSkipResultsWithOneUsage());
+  }
+}