BAEL-4392: Java Files Open Options

core-java-modules/core-java-io-3/src/test/java/com/baeldung/openoptions/OpenOptionsUnitTest.java

@@ -0,0 +1,96 @@
+package com.baeldung.openoptions;
+
+import org.hamcrest.CoreMatchers;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+
+import static org.junit.Assert.*;
+
+public class OpenOptionsUnitTest {
+
+    private static final String HOME = System.getProperty("user.home");
+    private static final String DUMMY_FILE_NAME = "sample.txt";
+    private static final String EXISTING_FILE_NAME = "existingFile.txt";
+
+    private static final String DUMMY_TEXT = "This is a sample text.";
+    private static final String ANOTHER_DUMMY_TEXT = "This is a another text.";
+
+    @BeforeClass
+    public static void beforeAll() throws IOException {
+        Path path = Paths.get(HOME, DUMMY_FILE_NAME);
+
+        try (OutputStream out = Files.newOutputStream(path)) {
+            out.write(DUMMY_TEXT.getBytes());
+        }
+
+        Files.createFile(Paths.get(HOME, EXISTING_FILE_NAME));
+    }
+
+    @AfterClass
+    public static void afterAll() throws IOException {
+        Files.delete(Paths.get(HOME, "newfile.txt"));
+        Files.delete(Paths.get(HOME, "sparse.txt"));
+        Files.delete(Paths.get(HOME, DUMMY_FILE_NAME));
+    }
+
+    @Test
+    public void givenExistingPath_whenCreateNewFile_thenCorrect() throws IOException {
+        Path path = Paths.get(HOME, "newfile.txt");
+        assertFalse(Files.exists(path));
+
+        Files.write(path, DUMMY_TEXT.getBytes(), StandardOpenOption.CREATE);
+        assertTrue(Files.exists(path));
+    }
+
+    @Test
+    public void givenExistingPath_whenReadExistingFile_thenCorrect() throws IOException {
+        Path path = Paths.get(HOME, DUMMY_FILE_NAME);
+
+        try (InputStream in = Files.newInputStream(path); BufferedReader reader = new BufferedReader(new InputStreamReader(in))) {
+            String line;
+            while ((line = reader.readLine()) != null) {
+                assertThat(line, CoreMatchers.containsString(DUMMY_TEXT));
+            }
+        }
+    }
+
+    @Test
+    public void givenExistingPath_whenWriteToExistingFile_thenCorrect() throws IOException {
+        Path path = Paths.get(HOME, DUMMY_FILE_NAME);
+
+        try (OutputStream out = Files.newOutputStream(path, StandardOpenOption.APPEND, StandardOpenOption.WRITE)) {
+            out.write(ANOTHER_DUMMY_TEXT.getBytes());
+        }
+    }
+
+    @Test
+    public void givenExistingPath_whenCreateSparseFile_thenCorrect() throws IOException {
+        Path path = Paths.get(HOME, "sparse.txt");
+        Files.write(path, DUMMY_TEXT.getBytes(), StandardOpenOption.CREATE_NEW, StandardOpenOption.SPARSE);
+    }
+
+    @Test
+    public void givenExistingPath_whenDeleteOnClose_thenCorrect() throws IOException {
+        Path path = Paths.get(HOME, EXISTING_FILE_NAME);
+        assertTrue(Files.exists(path)); // file was already created and exists
+
+        try (OutputStream out = Files.newOutputStream(path, StandardOpenOption.APPEND, StandardOpenOption.WRITE, StandardOpenOption.DELETE_ON_CLOSE)) {
+            out.write(ANOTHER_DUMMY_TEXT.getBytes());
+        }
+
+        assertFalse(Files.exists(path)); // file is deleted
+    }
+
+    @Test
+    public void givenExistingPath_whenWriteAndSync_thenCorrect() throws IOException {
+        Path path = Paths.get(HOME, DUMMY_FILE_NAME);
+        Files.write(path, ANOTHER_DUMMY_TEXT.getBytes(), StandardOpenOption.APPEND, StandardOpenOption.WRITE, StandardOpenOption.SYNC);
+    }
+}