setOutputStream now changes output of print statements

src/main/java/org/dynjs/runtime/ExecutionContext.java

@@ -1,5 +1,6 @@
 package org.dynjs.runtime;
 
+import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
@@ -23,9 +24,10 @@ public static ExecutionContext createGlobalExecutionContext(DynJS runtime) {
         context.clock = runtime.getConfig().getClock();
         context.timeZone = runtime.getConfig().getTimeZone();
         context.locale = runtime.getConfig().getLocale();
+        context.outputStream = runtime.getConfig().getOutputStream();
         return context;
     }
-    
+
     public static ExecutionContext createGlobalExecutionContext(DynJS runtime, InitializationListener listener) {
         ExecutionContext context = ExecutionContext.createEvalExecutionContext(runtime);
         listener.initialize(context);
@@ -51,6 +53,7 @@ public static ExecutionContext createEvalExecutionContext(DynJS runtime) {
     private TimeZone timeZone;
     private Locale locale;
     private Object functionReference;
+    private PrintStream outputStream;
 
     public ExecutionContext(ExecutionContext parent, LexicalEnvironment lexicalEnvironment, LexicalEnvironment variableEnvironment, Object thisBinding, boolean strict) {
         this.parent = parent;
@@ -60,6 +63,18 @@ public ExecutionContext(ExecutionContext parent, LexicalEnvironment lexicalEnvir
         this.strict = strict;
     }
 
+    public PrintStream getOutputStream() {
+        if (this.outputStream == null) {
+            if (this.getParent() == null) {
+                return System.out;
+            } else {
+                return this.getParent().getOutputStream();
+            }
+        } else {
+            return this.outputStream;
+        }
+    }
+
     public Object getFunctionReference() {
         return this.functionReference;
     }
@@ -558,7 +573,7 @@ public void collectStackElements(List<StackElement> elements) {
     public JSObject getPrototypeFor(String type) {
         return getGlobalObject().getPrototypeFor(type);
     }
-    
+
     public String toString() {
         return "ExecutionContext: " + System.identityHashCode( this ) + "; parent=" + this.parent;
     }

src/main/java/org/dynjs/runtime/builtins/Print.java

@@ -28,10 +28,10 @@ public Print(GlobalObject globalObject) {
 
     @Override
     public Object call(ExecutionContext context, Object self, Object... args) {
-        System.out.println(Types.toString(context, args[0]));
+        context.getOutputStream().println(Types.toString(context, args[0]));
         return Types.UNDEFINED;
     }
-    
+
     @Override
     public void setFileName() {
         this.filename = "org/dynjs/runtime/builtins/Print.java";

src/test/java/org/dynjs/runtime/OutputStreamTest.java

@@ -0,0 +1,31 @@
+package org.dynjs.runtime;
+
+import static org.fest.assertions.Assertions.*;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.io.UnsupportedEncodingException;
+import java.io.IOException;
+
+import org.dynjs.Config;
+import org.junit.Test;
+
+public class OutputStreamTest {
+    @Test
+    public void testOutputStream() throws UnsupportedEncodingException, IOException {
+      ByteArrayOutputStream bos = new ByteArrayOutputStream();
+      PrintStream ps = new PrintStream(bos);
+
+      Config config = new Config();
+      config.setOutputStream(ps);
+      DynJS dynjs = new DynJS(config);
+
+      dynjs.evaluate("print(\"hello world\");");
+
+      ps.flush();
+      bos.flush();
+      String result = bos.toString("UTF-8");
+
+      assertThat(result).isEqualTo("hello world\n");
+
+    }
+}