Autoformat was generating two undo action, the first one being an empty editor. Tested and fixed

Author: Federico Fissore

app/src/cc/arduino/packages/formatter/AStyle.java

@@ -92,8 +92,10 @@ public void run() {
     int line = getLineOfOffset(textArea);
     int lineOffset = getLineOffset(textArea, line);
 
+    editor.getTextArea().getUndoManager().beginInternalAtomicEdit();
     editor.setText(formattedText);
     editor.getSketch().setModified(true);
+    editor.getTextArea().getUndoManager().endInternalAtomicEdit();
 
     if (line != -1 && lineOffset != -1) {
       setCaretPosition(textArea, line, lineOffset);

app/test/processing/app/AutoformatProducesOneUndoActionTest.java

@@ -0,0 +1,56 @@
+package processing.app;
+
+import org.fest.swing.fixture.JMenuItemFixture;
+import org.junit.Test;
+import processing.app.helpers.RSyntaxTextAreaFixture;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+
+public class AutoformatProducesOneUndoActionTest extends AbstractGUITest {
+
+  public static final String SOURCE_BEFORE = "void setup() {\n" +
+          "              // put your setup code here, to run once:\n" +
+          "\n" +
+          "}\n" +
+          "\n" +
+          "void loop() {\n" +
+          "  // put your main code here, to run repeatedly:\n" +
+          "\n" +
+          "}";
+  public static final String SOURCE_AFTER = "void setup() {\n" +
+          "  // put your setup code here, to run once:\n" +
+          "\n" +
+          "}\n" +
+          "\n" +
+          "void loop() {\n" +
+          "  // put your main code here, to run repeatedly:\n" +
+          "\n" +
+          "}";
+
+  @Test
+  public void shouldSaveCaretPositionAfterAutoformat() {
+    JMenuItemFixture menuEditUndo = window.menuItem("menuEditUndo");
+    menuEditUndo.requireDisabled();
+
+    JMenuItemFixture menuToolsAutoFormat = window.menuItem("menuToolsAutoFormat");
+    menuToolsAutoFormat.requireEnabled();
+
+    RSyntaxTextAreaFixture editor = window.RSyntaxTextArea("editor");
+    editor.setText(SOURCE_BEFORE);
+
+    editor.setCaretPosition(29); // right before the first // (double slash)
+
+    menuToolsAutoFormat.click();
+
+    String formattedText = editor.getText();
+    assertEquals(SOURCE_AFTER, formattedText);
+
+    assertEquals(29, editor.getCaretPosition());
+
+    menuEditUndo.requireEnabled();
+    menuEditUndo.click();
+    assertEquals(SOURCE_BEFORE, editor.getText());
+  }
+
+}