tests: Added unit test for the IOHelper class.

src/test/java/com/owncloud/android/utils/IOHelperTest.java

@@ -0,0 +1,49 @@
+package com.owncloud.android.utils;
+
+import junit.framework.Assert;
+
+import org.junit.Test;
+
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.StringWriter;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static junit.framework.Assert.assertEquals;
+
+/**
+ * Unit tests for the ({@link IOHelper}) class.
+ */
+
+public class IOHelperTest {
+
+    private final static String outputFileName = "output.txt";
+
+    @Test
+    public void testInputStreamIsClosed() throws Exception {
+        // Define FileOutputStream for testing.
+        FileOutputStream mOutputStream = null;
+        StringWriter test = null;
+        try {
+            // init object
+            mOutputStream = new FileOutputStream(outputFileName);
+            test = new StringWriter();
+
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        } finally {
+            // Close output stream.
+            IOHelper.close(mOutputStream);
+        }
+        // try to write to stream. This should fail since we have now closed the output stream.
+        try {
+            mOutputStream.write("Hello World".getBytes());
+            Assert.fail("No exception was thrown");
+        } catch (IOException e) {
+            assertEquals(e.getMessage(), "Stream Closed");
+        }
+
+        Files.deleteIfExists(Paths.get(outputFileName));
+    }
+}