Refactor and add tests for TextBuffer (#738)

src/main/java/dan200/computercraft/core/terminal/TextBuffer.java

@@ -3,168 +3,84 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.terminal;
 
-public class TextBuffer {
+public class TextBuffer
-    private final char[] m_text;
+{
+    private final char[] text;
 
-    public TextBuffer(char c, int length) {
+    public TextBuffer( char c, int length )
-        this.m_text = new char[length];
+    {
-        for (int i = 0; i < length; i++) {
+        text = new char[length];
-            this.m_text[i] = c;
+        this.fill( c );
-        }
     }
 
-    public TextBuffer(String text) {
+    public TextBuffer( String text )
-        this(text, 1);
+    {
+        this.text = text.toCharArray();
     }
 
-    public TextBuffer(String text, int repetitions) {
+    public int length()
-        int textLength = text.length();
+    {
-        this.m_text = new char[textLength * repetitions];
+        return text.length;
-        for (int i = 0; i < repetitions; i++) {
-            for (int j = 0; j < textLength; j++) {
-                this.m_text[j + i * textLength] = text.charAt(j);
-            }
-        }
     }
 
-    public TextBuffer(TextBuffer text) {
+    public void write( String text )
-        this(text, 1);
+    {
+        write( text, 0 );
     }
 
-    public TextBuffer(TextBuffer text, int repetitions) {
+    public void write( String text, int start )
-        int textLength = text.length();
+    {
-        this.m_text = new char[textLength * repetitions];
-        for (int i = 0; i < repetitions; i++) {
-            for (int j = 0; j < textLength; j++) {
-                this.m_text[j + i * textLength] = text.charAt(j);
-            }
-        }
-    }
-
-    public int length() {
-        return this.m_text.length;
-    }
-
-    public char charAt(int i) {
-        return this.m_text[i];
-    }
-
-    public String read() {
-        return this.read(0, this.m_text.length);
-    }
-
-    public String read(int start, int end) {
-        start = Math.max(start, 0);
-        end = Math.min(end, this.m_text.length);
-        int textLength = Math.max(end - start, 0);
-        return new String(this.m_text, start, textLength);
-    }
-
-    public String read(int start) {
-        return this.read(start, this.m_text.length);
-    }
-
-    public void write(String text) {
-        this.write(text, 0, text.length());
-    }
-
-    public void write(String text, int start, int end) {
         int pos = start;
-        start = Math.max(start, 0);
+        start = Math.max( start, 0 );
-        end = Math.min(end, pos + text.length());
+        int end = Math.min( start + text.length(), pos + text.length() );
-        end = Math.min(end, this.m_text.length);
+        end = Math.min( end, this.text.length );
-        for (int i = start; i < end; i++) {
+        for( int i = start; i < end; i++ )
-            this.m_text[i] = text.charAt(i - pos);
+        {
+            this.text[i] = text.charAt( i - pos );
         }
     }
 
-    public void write(String text, int start) {
+    public void write( TextBuffer text )
-        this.write(text, start, start + text.length());
+    {
-    }
+        int end = Math.min( text.length(), this.text.length );
-
+        for( int i = 0; i < end; i++ )
-    public void write(TextBuffer text) {
+        {
-        this.write(text, 0, text.length());
+            this.text[i] = text.charAt( i );
-    }
-
-    public void write(TextBuffer text, int start, int end) {
-        int pos = start;
-        start = Math.max(start, 0);
-        end = Math.min(end, pos + text.length());
-        end = Math.min(end, this.m_text.length);
-        for (int i = start; i < end; i++) {
-            this.m_text[i] = text.charAt(i - pos);
         }
     }
 
-    public void write(TextBuffer text, int start) {
+    public void fill( char c )
-        this.write(text, start, start + text.length());
+    {
+        fill( c, 0, text.length );
     }
 
-    public void fill(char c) {
+    public void fill( char c, int start, int end )
-        this.fill(c, 0, this.m_text.length);
+    {
-    }
+        start = Math.max( start, 0 );
-
+        end = Math.min( end, text.length );
-    public void fill(char c, int start, int end) {
+        for( int i = start; i < end; i++ )
-        start = Math.max(start, 0);
+        {
-        end = Math.min(end, this.m_text.length);
+            text[i] = c;
-        for (int i = start; i < end; i++) {
-            this.m_text[i] = c;
         }
     }
 
-    public void fill(char c, int start) {
+    public char charAt( int i )
-        this.fill(c, start, this.m_text.length);
+    {
+        return text[i];
     }
 
-    public void fill(String text) {
+    public void setChar( int i, char c )
-        this.fill(text, 0, this.m_text.length);
+    {
-    }
+        if( i >= 0 && i < text.length )
-
+        {
-    public void fill(String text, int start, int end) {
+            text[i] = c;
-        int pos = start;
-        start = Math.max(start, 0);
-        end = Math.min(end, this.m_text.length);
-
-        int textLength = text.length();
-        for (int i = start; i < end; i++) {
-            this.m_text[i] = text.charAt((i - pos) % textLength);
         }
     }
 
-    public void fill(String text, int start) {
+    public String toString()
-        this.fill(text, start, this.m_text.length);
+    {
+        return new String( text );
     }
-
+}
-    public void fill(TextBuffer text) {
-        this.fill(text, 0, this.m_text.length);
-    }
-
-    public void fill(TextBuffer text, int start, int end) {
-        int pos = start;
-        start = Math.max(start, 0);
-        end = Math.min(end, this.m_text.length);
-
-        int textLength = text.length();
-        for (int i = start; i < end; i++) {
-            this.m_text[i] = text.charAt((i - pos) % textLength);
-        }
-    }
-
-    public void fill(TextBuffer text, int start) {
-        this.fill(text, start, this.m_text.length);
-    }
-
-    public void setChar(int i, char c) {
-        if (i >= 0 && i < this.m_text.length) {
-            this.m_text[i] = c;
-        }
-    }
-
-    @Override
-    public String toString() {
-        return new String(this.m_text);
-    }
-}

src/test/java/dan200/computercraft/core/terminal/TextBufferTest.java

@@ -0,0 +1,150 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.core.terminal;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class TextBufferTest
+{
+    @Test
+    void testStringConstructor()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        assertEquals( "test", textBuffer.toString() );
+    }
+
+    @Test
+    void testCharRepetitionConstructor()
+    {
+        TextBuffer textBuffer = new TextBuffer( 'a', 5 );
+        assertEquals( "aaaaa", textBuffer.toString() );
+    }
+
+    @Test
+    void testLength()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        assertEquals( 4, textBuffer.length() );
+    }
+
+    @Test
+    void testWrite()
+    {
+        TextBuffer textBuffer = new TextBuffer( ' ', 4 );
+        textBuffer.write( "test" );
+        assertEquals( "test", textBuffer.toString() );
+    }
+
+    @Test
+    void testWriteTextBuffer()
+    {
+        TextBuffer source = new TextBuffer( "test" );
+        TextBuffer target = new TextBuffer( "    " );
+        target.write( source );
+        assertEquals( "test", target.toString() );
+    }
+
+    @Test
+    void testWriteFromPos()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.write( "il", 1 );
+        assertEquals( "tilt", textBuffer.toString() );
+    }
+
+    @Test
+    void testWriteOutOfBounds()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.write( "abcdefghijklmnop", -5 );
+        assertEquals( "fghi", textBuffer.toString() );
+    }
+
+    @Test
+    void testWriteOutOfBounds2()
+    {
+        TextBuffer textBuffer = new TextBuffer( "             " );
+        textBuffer.write( "Hello, world!", -3 );
+        assertEquals( "lo, world!   ", textBuffer.toString() );
+    }
+
+    @Test
+    void testFill()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.fill( 'c' );
+        assertEquals( "cccc", textBuffer.toString() );
+    }
+
+    @Test
+    void testFillSubstring()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.fill( 'c', 1, 3 );
+        assertEquals( "tcct", textBuffer.toString() );
+    }
+
+    @Test
+    void testFillOutOfBounds()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.fill( 'c', -5, 5 );
+        assertEquals( "cccc", textBuffer.toString() );
+    }
+
+    @Test
+    void testCharAt()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        assertEquals( 'e', textBuffer.charAt( 1 ) );
+    }
+
+    @Test
+    void testSetChar()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.setChar( 2, 'n' );
+        assertEquals( "tent", textBuffer.toString() );
+    }
+
+    @Test
+    void testSetCharWithNegativeIndex()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.setChar( -5, 'n' );
+        assertEquals( "test", textBuffer.toString(), "Buffer should not change after setting char with negative index." );
+    }
+
+    @Test
+    void testSetCharWithIndexBeyondBufferEnd()
+    {
+        TextBuffer textBuffer = new TextBuffer( "test" );
+        textBuffer.setChar( 10, 'n' );
+        assertEquals( "test", textBuffer.toString(), "Buffer should not change after setting char beyond buffer end." );
+    }
+
+    @Test
+    void testMultipleOperations()
+    {
+        TextBuffer textBuffer = new TextBuffer( ' ', 5 );
+        textBuffer.setChar( 0, 'H' );
+        textBuffer.setChar( 1, 'e' );
+        textBuffer.setChar( 2, 'l' );
+        textBuffer.write( "lo", 3 );
+        assertEquals( "Hello", textBuffer.toString(), "TextBuffer failed to persist over multiple operations." );
+    }
+
+    @Test
+    void testEmptyBuffer()
+    {
+        TextBuffer textBuffer = new TextBuffer( "" );
+        // exception on writing to empty buffer would fail the test
+        textBuffer.write( "test" );
+        assertEquals( "", textBuffer.toString() );
+    }
+}