add Tests

demo1/src/main/resources/testfile.md

+test
\ No newline at end of file

demo1/src/test/java/cn/freemud/demo/IOTests.java

 package cn.freemud.demo;
 
+import com.google.common.base.Charsets;
+import com.google.common.base.Joiner;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Iterators;
+import com.google.common.collect.Lists;
+import com.google.common.io.Files;
+import com.google.common.io.Resources;
+import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.List;
+
+import static com.google.common.base.Preconditions.*;
+
 public class IOTests {
 
     @Test
     public void Test(){
 
+        String content = "this is test file.";
+        String fileName = "D:/java-traning/test1.md";
+        checkNotNull(fileName,"test fileName must not be null.");
+
+        File testFile = new File(fileName);
+        try {
+
+            // write file.
+            if(testFile.isDirectory()){
+                if(testFile.exists()){
+                    testFile.delete();
+                }
+            }
+            else{
+                testFile.mkdirs();
+            }
+            Files.write(content,testFile, Charsets.UTF_8);
+
+            // read file
+
+            String readFileContent = Joiner.on("\r\n").join(Files.readLines(testFile,Charsets.UTF_8));
+
+            Assert.assertEquals(content,readFileContent);
+        }
+        catch (IOException fileIoEx){
+            String ss = fileIoEx.toString();
+            System.out.print(ss);
+
+        }
     }
 }