Added Charset parameter and fix UTs for cp1252 charset

src/main/java/org/codehaus/mojo/exec/LineRedirectOutputStream.java

@@ -22,6 +22,7 @@
 import java.io.ByteArrayOutputStream;
 import java.io.OutputStream;
 import java.nio.charset.Charset;
+import java.util.Objects;
 import java.util.function.Consumer;
 
 /**
@@ -35,10 +36,16 @@
 class LineRedirectOutputStream extends OutputStream {
 
     private final Consumer<String> linePrinter;
+    private final Charset charset;
     private ByteArrayOutputStream buffer = new ByteArrayOutputStream();
 
     public LineRedirectOutputStream(Consumer<String> linePrinter) {
-        this.linePrinter = linePrinter;
+        this(linePrinter, Charset.defaultCharset());
+    }
+
+    public LineRedirectOutputStream(Consumer<String> linePrinter, Charset charset) {
+        this.linePrinter = Objects.requireNonNull(linePrinter);
+        this.charset = Objects.requireNonNull(charset);
     }
 
     @Override
@@ -63,7 +70,7 @@ public void close() {
     }
 
     private void printAndReset() {
-        linePrinter.accept(new String(buffer.toByteArray(), Charset.defaultCharset()));
+        linePrinter.accept(new String(buffer.toByteArray(), charset));
         buffer = new ByteArrayOutputStream();
     }
 }

src/test/java/org/codehaus/mojo/exec/LineRedirectOutputStreamTest.java

@@ -1,23 +1,74 @@
 package org.codehaus.mojo.exec;
 
 import org.junit.Assert;
+import org.junit.Assume;
 import org.junit.Test;
 
 import java.io.IOException;
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.function.Function;
 
 public class LineRedirectOutputStreamTest {
 
     @Test
-    public void givenUtf8Output_whenRedirecting_thenShouldDecodeProperly() throws IOException {
+    public void givenExtendedUnicodeCharacterOutput_whenRedirectingWithUtf8Charset_thenShouldDecodeProperly()
+            throws IOException {
+        internalTestForCharset(StandardCharsets.UTF_8);
+    }
+
+    @Test
+    public void givenExtendedUnicodeCharacterOutput_whenRedirectingWithIso8859Charset_thenShouldDecodeProperly()
+            throws IOException {
+        internalTestForCharset(StandardCharsets.ISO_8859_1);
+    }
+
+    @Test
+    public void givenExtendedUnicodeCharacterOutput_whenRedirectingWithCp1252_thenShouldDecodeProperly()
+            throws IOException {
+        Assume.assumeTrue("The JVM does not contain the cp-1252 charset", Charset.availableCharsets().containsKey("windows-1252"));
+        internalTestForCharset(Charset.forName("windows-1252"));
+    }
+
+    @Test
+    public void givenExtendedUnicodeCharacterOutput_whenRedirectingWithDefaultCharset_thenShouldDecodeProperly()
+            throws IOException {
+        internalTestForCharset(Charset.defaultCharset());
+    }
+
+    @Test
+    public void givenExtendedUnicodeCharacterOutput_whenRedirectingWithCharsetUnspecified_thenShouldDecodeProperly()
+            throws IOException {
+        internalTestForCharset(sb -> new LineRedirectOutputStream(sb::append), Charset.defaultCharset());
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void givenNullCharset_whenInstantiating_thenShouldThrow() {
+        new LineRedirectOutputStream(new StringBuilder()::append, null);
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void givenNullStringConsumer_whenInstantiating_thenShouldThrow() {
+        new LineRedirectOutputStream(null, Charset.defaultCharset());
+    }
+
+    private void internalTestForCharset(Charset charset) throws IOException {
+        internalTestForCharset(sb -> new LineRedirectOutputStream(sb::append, charset), charset);
+    }
+
+    private void internalTestForCharset(Function<StringBuilder, LineRedirectOutputStream> lineRedirectOutputStream,
+                                        Charset charset) throws IOException {
         StringBuilder sb = new StringBuilder();
-        String firstLine = "Hello 😃 😄";
-        String secondLine = "foo bar éà";
+        String firstLine = "Hello, 你好, नमस्ते, مرحبا, γεια σας, שלום, こんにちは, 안녕하세요!";
+        String secondLine = "🌍 Welcome to the world! 🌟✨🎉🔥";
+        String expectedString = firstLine + secondLine;
 
-        try (LineRedirectOutputStream os = new LineRedirectOutputStream(sb::append)) {
-            os.write(String.join("\n", firstLine, secondLine).getBytes(Charset.defaultCharset()));
+        try (LineRedirectOutputStream os = lineRedirectOutputStream.apply(sb)) {
+            os.write(String.join("\n", firstLine, secondLine).getBytes(charset));
         }
 
-        Assert.assertEquals(firstLine + secondLine, sb.toString());
+        // The String to bytes to String is required here because StringCoding uses the Charset.defaultCharset()
+        // internally so it would make the test fail when testing for different charsets.
+        Assert.assertEquals(new String(expectedString.getBytes(charset), charset), sb.toString());
     }
 }