List files within directory

Issue: BAEL-2447

core-java-io/src/test/java/com/baeldung/file/ListFilesUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.file;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.Test;
+
+import com.baeldung.files.ListFiles;
+
+public class ListFilesUnitTest {
+
+    private ListFiles listFiles = new ListFiles();
+    private String DIRECTORY = "src/test/resources/listFilesUnitTestFolder";
+    private static final int DEPTH = 1;
+    private Set<String> EXPECTED_FILE_LIST = new HashSet<String>() {
+        {
+            add("test.xml");
+            add("employee.json");
+            add("students.json");
+            add("country.txt");
+        }
+    };
+
+    @Test
+    public void givenDir_whenUsingJAVAIO_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingJavaIO(DIRECTORY));
+    }
+
+    @Test
+    public void givenDir_whenWalkingTree_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingFileWalk(DIRECTORY,DEPTH));
+    }
+
+    @Test
+    public void givenDir_whenWalkingTreeWithVisitor_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingFileWalkAndVisitor(DIRECTORY));
+    }
+
+    @Test
+    public void givenDir_whenUsingDirectoryStream_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingDirectoryStream(DIRECTORY));
+    }
+}