diff --git a/core-java/src/main/resources/countries.properties b/core-java/src/main/resources/countries.properties
new file mode 100644
index 0000000000..3c1f53aded
--- /dev/null
+++ b/core-java/src/main/resources/countries.properties
@@ -0,0 +1,3 @@
+UK
+US
+Germany
diff --git a/core-java/src/main/java/com/baeldung/file/FileOutputStreamTest.java b/core-java/src/test/java/com/baeldung/file/FileOutputStreamTest.java
similarity index 96%
rename from core-java/src/main/java/com/baeldung/file/FileOutputStreamTest.java
rename to core-java/src/test/java/com/baeldung/file/FileOutputStreamTest.java
index d85c028dae..451c1b4c4d 100644
--- a/core-java/src/main/java/com/baeldung/file/FileOutputStreamTest.java
+++ b/core-java/src/test/java/com/baeldung/file/FileOutputStreamTest.java
@@ -14,7 +14,7 @@ import com.baeldung.util.StreamUtils;
 
 public class FileOutputStreamTest {
 
-    public static final String fileName = "src/main/resources/countries.txt";
+    public static final String fileName = "src/main/resources/countries.properties";
 
     @Test
     public void whenAppendToFileUsingFileOutputStream_thenCorrect() throws Exception {
@@ -30,7 +30,6 @@ public class FileOutputStreamTest {
     @After
     public void revertFile() throws IOException {
         PrintWriter writer = new PrintWriter(fileName);
-        writer.print("");
         writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
         writer.close();
     }
diff --git a/core-java/src/main/java/com/baeldung/file/FileUtilsTest.java b/core-java/src/test/java/com/baeldung/file/FileUtilsTest.java
similarity index 96%
rename from core-java/src/main/java/com/baeldung/file/FileUtilsTest.java
rename to core-java/src/test/java/com/baeldung/file/FileUtilsTest.java
index 6147653976..9ee8726575 100644
--- a/core-java/src/main/java/com/baeldung/file/FileUtilsTest.java
+++ b/core-java/src/test/java/com/baeldung/file/FileUtilsTest.java
@@ -16,7 +16,7 @@ import com.baeldung.util.StreamUtils;
 
 public class FileUtilsTest {
 
-    public static final String fileName = "src/main/resources/countries.txt";
+    public static final String fileName = "src/main/resources/countries.properties";
 
     @Test
     public void whenAppendToFileUsingFiles_thenCorrect() throws IOException {
@@ -31,7 +31,6 @@ public class FileUtilsTest {
     @After
     public void revertFile() throws IOException {
         PrintWriter writer = new PrintWriter(fileName);
-        writer.print("");
         writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
         writer.close();
     }
diff --git a/core-java/src/main/java/com/baeldung/file/FileWriterTest.java b/core-java/src/test/java/com/baeldung/file/FileWriterTest.java
similarity index 90%
rename from core-java/src/main/java/com/baeldung/file/FileWriterTest.java
rename to core-java/src/test/java/com/baeldung/file/FileWriterTest.java
index 67e4dfaf20..8d2ce4310e 100644
--- a/core-java/src/main/java/com/baeldung/file/FileWriterTest.java
+++ b/core-java/src/test/java/com/baeldung/file/FileWriterTest.java
@@ -15,11 +15,10 @@ import com.baeldung.util.StreamUtils;
 
 public class FileWriterTest {
     
-    public static final String fileName = "src/main/resources/countries.txt";
+    public static final String fileName = "src/main/resources/countries.properties";
 
     @Test
     public void whenAppendToFileUsingFileWriter_thenCorrect() throws IOException {
-        String fileName = "src/main/resources/countries.txt";
         FileWriter fw = new FileWriter(fileName, true);
         BufferedWriter bw = new BufferedWriter(fw);
         bw.write("Spain");
@@ -29,13 +28,12 @@ public class FileWriterTest {
         assertThat(
           StreamUtils.getStringFromInputStream(
           new FileInputStream(fileName)))
-          .isEqualTo("UK\r\n" + "US\r\n" + "Germany\r\n" + "Spain\r\n");
+          .isEqualTo("UK\r\n" + "US\r\n" + "Germany\r\n" + "Spain\n");
     }
 
     @After
     public void revertFile() throws IOException {
         PrintWriter writer = new PrintWriter(fileName);
-        writer.print("");
         writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
         writer.close();
     }
diff --git a/core-java/src/main/java/com/baeldung/file/FilesTest.java b/core-java/src/test/java/com/baeldung/file/FilesTest.java
similarity index 96%
rename from core-java/src/main/java/com/baeldung/file/FilesTest.java
rename to core-java/src/test/java/com/baeldung/file/FilesTest.java
index 0ca69db8ab..bd39d004d3 100644
--- a/core-java/src/main/java/com/baeldung/file/FilesTest.java
+++ b/core-java/src/test/java/com/baeldung/file/FilesTest.java
@@ -16,7 +16,7 @@ import com.baeldung.util.StreamUtils;
 
 public class FilesTest {
 
-    public static final String fileName = "src/main/resources/countries.txt";
+    public static final String fileName = "src/main/resources/countries.properties";
 
     @Test
     public void whenAppendToFileUsingFiles_thenCorrect() throws IOException {
@@ -30,7 +30,6 @@ public class FilesTest {
     @After
     public void revertFile() throws IOException {
         PrintWriter writer = new PrintWriter(fileName);
-        writer.print("");
         writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
         writer.close();
     }
diff --git a/core-java/src/main/java/com/baeldung/file/GuavaTest.java b/core-java/src/test/java/com/baeldung/file/GuavaTest.java
similarity index 76%
rename from core-java/src/main/java/com/baeldung/file/GuavaTest.java
rename to core-java/src/test/java/com/baeldung/file/GuavaTest.java
index 06379451f9..5a7ec6c4a8 100644
--- a/core-java/src/main/java/com/baeldung/file/GuavaTest.java
+++ b/core-java/src/test/java/com/baeldung/file/GuavaTest.java
@@ -8,6 +8,7 @@ import java.io.IOException;
 import java.io.PrintWriter;
 
 import org.junit.After;
+import org.junit.Before;
 import org.junit.Test;
 
 import com.baeldung.util.StreamUtils;
@@ -18,10 +19,17 @@ import com.google.common.io.Files;
 
 public class GuavaTest {
 
-    public static final String fileName = "src/main/resources/countries.txt";
+    public static final String fileName = "src/main/resources/countries.properties";
+    
+    @Before
+    public void setup() throws Exception {
+        PrintWriter writer = new PrintWriter(fileName);
+        writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
+        writer.close();
+    }
 
     @Test
-    public void whenAppendToFileUsingFileWriter_thenCorrect() throws IOException {
+    public void whenAppendToFileUsingGuava_thenCorrect() throws IOException {
         File file = new File(fileName);
         CharSink chs = Files.asCharSink(file, Charsets.UTF_8, FileWriteMode.APPEND);
         chs.write("Spain\r\n");
@@ -34,7 +42,6 @@ public class GuavaTest {
     @After
     public void revertFile() throws IOException {
         PrintWriter writer = new PrintWriter(fileName);
-        writer.print("");
         writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
         writer.close();
     }