Add failing tests for #216.

richtextfx/src/test/java/org/fxmisc/richtext/ParagraphTest.java

@@ -0,0 +1,22 @@
+package org.fxmisc.richtext;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class ParagraphTest {
+
+    // Tests that when concatenating two paragraphs,
+    // the style of the first one is used for the result.
+    // This relates to merging text changes and issue #216.
+    @Test
+    public void concatEmptyParagraphsTest() {
+        Paragraph<Boolean, Void> p1 = new Paragraph<>(null, "", true);
+        Paragraph<Boolean, Void> p2 = new Paragraph<>(null, "", false);
+
+        Paragraph<Boolean, Void> p = p1.concat(p2);
+
+        assertEquals(Boolean.TRUE, p.getStyleAtPosition(0));
+    }
+
+}

richtextfx/src/test/java/org/fxmisc/richtext/StyledTextAreaModelTest.java

@@ -1,13 +1,12 @@
 package org.fxmisc.richtext;
 
 import static org.junit.Assert.*;
-import javafx.embed.swing.JFXPanel;
-
-import org.junit.Test;
 
 import java.util.Collection;
 import java.util.Collections;
 
+import org.junit.Test;
+
 public class StyledTextAreaModelTest {
 
     @Test
@@ -28,4 +27,25 @@ public void testUndoWithWinNewlines() {
         assertEquals("abc\ndef", model.getText());
     }
 
+    @Test
+    public void testForBug216() {
+        // set up area with some styled text content
+        boolean initialStyle = false;
+        StyledTextAreaModel<Boolean, String> model = new StyledTextAreaModel<>(
+                initialStyle, "", new EditableStyledDocument<>(initialStyle, ""), true);
+        model.replaceText("testtest");
+        model.setStyle(0, 8, true);
+
+        // add a space styled by initialStyle
+        model.setUseInitialStyleForInsertion(true);
+        model.insertText(4, " ");
+
+        // add another space
+        model.insertText(5, " ");
+
+        // testing that undo/redo don't throw an exception
+        model.undo();
+        model.redo();
+    }
+
 }