BAEL-3214 | Unit tests for class FileWriter

Nikunj Gandhi · Nikunj Gandhi · commit f66e0d805398 · 2019-09-08T16:27:20.000-04:00
diff --git a/core-java-modules/core-java-io-2/src/test/java/com/baeldung/filewriter/FileWriterExampleTest.java b/core-java-modules/core-java-io-2/src/test/java/com/baeldung/filewriter/FileWriterExampleTest.java
@@ -0,0 +1,123 @@
+package com.baeldung.filewriter;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.junit.After;
+import org.junit.Test;
+
+public class FileWriterExampleTest {
+
+    @After
+    public void tearDown() throws IOException {
+        Files.delete(Path.of("src/test/resources/FileWriterTest.txt"));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_FileName() throws IOException {
+        try (FileWriter fileWriter = new FileWriter("src/test/resources/FileWriterTest.txt")) {
+            fileWriter.write("Hello Folks!");
+        }
+
+        assertEquals("Hello Folks!", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_FileName_And_Charset() throws IOException {
+        try (FileWriter fileWriter = new FileWriter("src/test/resources/FileWriterTest.txt", Charset.forName("US-ASCII"))) {
+            fileWriter.write("Hello Folks! Let us learn the Façade design pattern");
+        }
+        
+        System.out.println(new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+       assertEquals("Hello Folks! Let us learn the Fa?ade design pattern", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_FileName_And_AppendFlag() throws IOException {
+        try (FileWriter fileWriter = new FileWriter("src/test/resources/FileWriterTest.txt")) {
+            fileWriter.write("Hello Folks!");
+        }
+
+        try (FileWriter fileWriter = new FileWriter("src/test/resources/FileWriterTest.txt", true)) {
+            fileWriter.write("Let us learn the Façade design pattern");
+        }
+
+        assertEquals("Hello Folks!Let us learn the Façade design pattern", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_FileName_And_Charset_And_AppendFlag() throws IOException {
+        try (FileWriter fileWriter = new FileWriter("src/test/resources/FileWriterTest.txt", Charset.forName("US-ASCII"))) {
+            fileWriter.write("Hello Folks!");
+        }
+
+        try (FileWriter fileWriter = new FileWriter("src/test/resources/FileWriterTest.txt", Charset.forName("US-ASCII"), true)) {
+            fileWriter.write("Let us learn the Façade design pattern");
+        }
+        
+        assertEquals("Hello Folks!Let us learn the Fa?ade design pattern", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_File() throws IOException {
+        try (FileWriter fileWriter = new FileWriter(new File("src/test/resources/FileWriterTest.txt"))) {
+            fileWriter.write("Hello Folks!");
+        }
+
+        assertEquals("Hello Folks!", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_File_And_Charset() throws IOException {
+        try (FileWriter fileWriter = new FileWriter(new File("src/test/resources/FileWriterTest.txt"), Charset.forName("US-ASCII"))) {
+            fileWriter.write("Hello Folks!Let us learn the Façade design pattern");
+        }
+        
+        assertEquals("Hello Folks!Let us learn the Fa?ade design pattern", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_File_And_AppendFlag() throws IOException {
+        try (FileWriter fileWriter = new FileWriter(new File("src/test/resources/FileWriterTest.txt"))) {
+            fileWriter.write("Hello Folks!");
+        }
+
+        try (FileWriter fileWriter = new FileWriter(new File("src/test/resources/FileWriterTest.txt"), true)) {
+            fileWriter.write("Let us learn the Façade design pattern");
+        }
+
+        assertEquals("Hello Folks!Let us learn the Façade design pattern", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+    @Test
+    public void testFileWriter_Constructor_With_File_And_Charset_And_AppendFlag() throws IOException {
+        try (FileWriter fileWriter = new FileWriter(new File("src/test/resources/FileWriterTest.txt"), Charset.forName("US-ASCII"))) {
+            fileWriter.write("Hello Folks!");
+        }
+
+        try (FileWriter fileWriter = new FileWriter(new File("src/test/resources/FileWriterTest.txt"), Charset.forName("US-ASCII"), true)) {
+            fileWriter.write("Let us learn the Façade design pattern");
+        }
+        
+        assertEquals("Hello Folks!Let us learn the Fa?ade design pattern", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+    
+    @Test
+    public void testFileWriter_Constructor_With_FileDescriptor() throws FileNotFoundException, IOException {
+        try(FileOutputStream fos = new FileOutputStream(new File("src/test/resources/FileWriterTest.txt"));
+            FileWriter fileWriter = new FileWriter(fos.getFD())){
+            fileWriter.write("Hello Folks!");        
+        }
+        
+        assertEquals("Hello Folks!", new String(Files.readAllBytes(Path.of("src/test/resources/FileWriterTest.txt"))));
+    }
+
+}
