Fix #475: Improved caret behavior on first and last lines

RSyntaxTextArea/src/main/java/org/fife/ui/rsyntaxtextarea/RSyntaxUtilities.java

@@ -841,7 +841,7 @@ public static int getPositionAbove(RSyntaxTextArea c, int offs,
 		TokenOrientedView tov = (TokenOrientedView)e;
 		Token token = tov.getTokenListForPhysicalLineAbove(offs);
 		if (token==null) {
-			return -1;
+			return 0;
 		}
 		else if (token.getType()==Token.NULL) {
 			int line = c.getLineOfOffset(offs);	// Sure to be >0 ??
@@ -875,7 +875,7 @@ public static int getPositionBelow(RSyntaxTextArea c, int offs,
 		TokenOrientedView tov = (TokenOrientedView)e;
 		Token token = tov.getTokenListForPhysicalLineBelow(offs);
 		if (token==null) {
-			return -1;
+			return c.getDocument().getLength();
 		}
 		else if (token.getType()==Token.NULL) {
 			int line = c.getLineOfOffset(offs);	// Sure to be > c.getLineCount()-1 ??

RSyntaxTextArea/src/main/java/org/fife/ui/rsyntaxtextarea/SyntaxView.java

@@ -431,9 +431,6 @@ public Token getTokenListForPhysicalLineAbove(int offset) {
 				return document.getTokenListForLine(line);
 			}
 		}
-		//		int line = map.getElementIndex(offset) - 1;
-		//		if (line>=0)
-		//			return document.getTokenListForLine(line);
 		return null;
 	}
 

RSyntaxTextArea/src/test/java/org/fife/ui/rsyntaxtextarea/SyntaxViewTest.java

@@ -4,23 +4,61 @@
  */
 package org.fife.ui.rsyntaxtextarea;
 
-
+import org.fife.ui.SwingRunnerExtension;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
+import javax.swing.*;
 import javax.swing.text.BadLocationException;
 import javax.swing.text.Position;
 import java.awt.*;
 
+
 /**
  * Unit tests for the {@code SyntaxView} class.
  *
  * @author Robert Futrell
  * @version 1.0
  */
+@ExtendWith(SwingRunnerExtension.class)
 class SyntaxViewTest extends AbstractRSyntaxTextAreaTest {
 
 
+	@Test
+	void testGetNextVisualPositionFrom_north_onFirstLine() throws BadLocationException {
+
+		String content = "This is the text";
+		RSyntaxTextArea textArea = createTextArea(SyntaxConstants.SYNTAX_STYLE_NONE, content);
+		textArea.setCaretPosition(content.indexOf("is"));
+
+		SyntaxView view = (SyntaxView)textArea.getUI().getRootView(textArea).getView(0);
+		Position.Bias[] biasRet = new Position.Bias[1];
+
+		// Pressing the up arrow on the top line moves the caret to offset 0
+		int actual = view.getNextVisualPositionFrom(textArea.getCaretPosition(),
+			Position.Bias.Backward, textArea.getBounds(), SwingConstants.NORTH, biasRet);
+		Assertions.assertEquals(0, actual);
+	}
+
+
+	@Test
+	void testGetNextVisualPositionFrom_south_onLastLine() throws BadLocationException {
+
+		String content = "This is the text";
+		RSyntaxTextArea textArea = createTextArea(SyntaxConstants.SYNTAX_STYLE_NONE, content);
+		textArea.setCaretPosition(content.indexOf("is"));
+
+		SyntaxView view = (SyntaxView)textArea.getUI().getRootView(textArea).getView(0);
+		Position.Bias[] biasRet = new Position.Bias[1];
+
+		// Pressing the up arrow on the top line moves the caret to offset 0
+		int actual = view.getNextVisualPositionFrom(textArea.getCaretPosition(),
+			Position.Bias.Forward, textArea.getBounds(), SwingConstants.SOUTH, biasRet);
+		Assertions.assertEquals(content.length(), actual);
+	}
+
+
 	@Test
 	void testGetTokenListForPhysicalLineAbove_foldingEnabled() throws BadLocationException {
 
@@ -150,7 +188,13 @@ void testNextTabStop_tabSize0() {
 	void testPaint_foldedFolds() {
 
 		RSyntaxTextArea textArea = createTextArea();
-		textArea.getFoldManager().getFold(0).setCollapsed(true);
-		textArea.paintImmediately(textArea.getVisibleRect());
+		// Fold one child fold so there is a mix of expanded and collapsed folds,
+		// and there is > 1 line at all
+		textArea.getFoldManager().getFold(0).getChild(0).setCollapsed(true);
+		textArea.setCaretPosition(1);
+		textArea.moveCaretPosition(textArea.getDocument().getLength() - 1);
+
+		SyntaxView view = (SyntaxView) textArea.getUI().getRootView(textArea).getView(0);
+		view.paint(createTestGraphics(), textArea.getVisibleRect());
 	}
 }