[Core, TestNg] Clean up stream closing

  Refactored the code around streams so it follows these rules:
   - Streams should be closed by their owners
   - A stream is owned by its creator or when provided as a constructor argument
   - Stream ownership should be the smallest possible unit. The method, class, process, system.
   - System.out and System.error may never be closed

 Fixes #1108

core/src/main/java/cucumber/api/formatter/NiceAppendable.java

@@ -65,7 +65,7 @@ public NiceAppendable println(CharSequence csq) {
     public void close() {
         try {
             tryFlush();
-            if (out instanceof Closeable && out != System.out && out != System.err) {
+            if (out instanceof Closeable) {
                 ((Closeable) out).close();
             }
         } catch (IOException e) {

core/src/main/java/cucumber/runtime/formatter/HTMLFormatter.java

@@ -119,12 +119,12 @@ public void receive(TestRunFinished event) {
     };
 
     public HTMLFormatter(URL htmlReportDir) {
-        this.htmlReportDir = htmlReportDir;
+        this(htmlReportDir, null);
     }
 
-    public HTMLFormatter(URL htmlReportDir, NiceAppendable jsOut) {
-        this(htmlReportDir);
-        this.jsOut = jsOut;
+    HTMLFormatter(URL htmlReportDir, NiceAppendable optionalJsOut) {
+        this.htmlReportDir = htmlReportDir;
+        this.jsOut = optionalJsOut; // For testing purposes
     }
 
     @Override
@@ -188,7 +188,7 @@ private void handleEmbed(EmbedEvent event) {
             String extension = MIME_TYPES_EXTENSIONS.get(mimeType);
             if (extension != null) {
                 StringBuilder fileName = new StringBuilder("embedded").append(embeddedIndex++).append(".").append(extension);
-                writeBytesAndClose(event.data, reportFileOutputStream(fileName.toString()));
+                writeBytesToURL(event.data, toUrl(fileName.toString()));
                 jsFunctionCall("embedding", mimeType, fileName);
             }
         }
@@ -463,50 +463,72 @@ private void copyReportFiles() {
             if (textAssetStream == null) {
                 throw new CucumberException("Couldn't find " + textAsset + ". Is cucumber-html on your classpath? Make sure you have the right version.");
             }
-            String baseName = new File(textAsset).getName();
-            writeStreamAndClose(textAssetStream, reportFileOutputStream(baseName));
+            String fileName = new File(textAsset).getName();
+            writeStreamToURL(textAssetStream, toUrl(fileName));
+        }
+    }
+
+    private URL toUrl(String fileName) {
+        try {
+            return new URL(htmlReportDir, fileName);
+        } catch (IOException e) {
+           throw new CucumberException(e);
         }
     }
 
-    private void writeStreamAndClose(InputStream in, OutputStream out) {
+    private static void writeStreamToURL(InputStream in, URL url) {
+        OutputStream out = createReportFileOutputStream(url);
+
         byte[] buffer = new byte[16 * 1024];
         try {
             int len = in.read(buffer);
             while (len != -1) {
                 out.write(buffer, 0, len);
                 len = in.read(buffer);
             }
-            out.close();
         } catch (IOException e) {
             throw new CucumberException("Unable to write to report file item: ", e);
+        } finally {
+            closeQuietly(out);
         }
     }
 
-    private void writeBytesAndClose(byte[] buf, OutputStream out) {
+    private static void writeBytesToURL(byte[] buf, URL url) throws CucumberException {
+        OutputStream reportFileOutputStream = createReportFileOutputStream(url);
         try {
-            out.write(buf);
+            reportFileOutputStream.write(buf);
         } catch (IOException e) {
             throw new CucumberException("Unable to write to report file item: ", e);
+        } finally {
+            closeQuietly(reportFileOutputStream);
         }
     }
 
     private NiceAppendable jsOut() {
         if (jsOut == null) {
             try {
-                jsOut = new NiceAppendable(new OutputStreamWriter(reportFileOutputStream(JS_REPORT_FILENAME), "UTF-8"));
+                jsOut = new NiceAppendable(new OutputStreamWriter(createReportFileOutputStream(toUrl(JS_REPORT_FILENAME)), "UTF-8"));
             } catch (IOException e) {
                 throw new CucumberException(e);
             }
         }
         return jsOut;
     }
 
-    private OutputStream reportFileOutputStream(String fileName) {
+    private static OutputStream createReportFileOutputStream(URL url) {
         try {
-            return new URLOutputStream(new URL(htmlReportDir, fileName));
+            return new URLOutputStream(url);
         } catch (IOException e) {
             throw new CucumberException(e);
         }
     }
 
+    private static void closeQuietly(OutputStream out) {
+        try {
+            out.close();
+        } catch (IOException ignored) {
+            // go gentle into that good night
+        }
+    }
+
 }

testng/src/main/java/cucumber/api/testng/TestNGCucumberRunner.java

@@ -11,6 +11,7 @@
 import cucumber.runtime.io.ResourceLoaderClassFinder;
 import cucumber.runtime.model.CucumberFeature;
 
+import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -36,7 +37,12 @@ public TestNGCucumberRunner(Class clazz) {
         RuntimeOptionsFactory runtimeOptionsFactory = new RuntimeOptionsFactory(clazz);
         runtimeOptions = runtimeOptionsFactory.create();
 
-        reporter = new TestNgReporter(System.out);
+        reporter = new TestNgReporter(new PrintStream(System.out) {
+                @Override
+                public void close() {
+                    // We have no intention to close System.out
+                }
+            });
         ClassFinder classFinder = new ResourceLoaderClassFinder(resourceLoader, classLoader);
         resultListener = new FeatureResultListener(runtimeOptions.isStrict());
         runtime = new Runtime(resourceLoader, classFinder, classLoader, runtimeOptions);