Guide to BufferedReader

Issue: BAEL-2255

core-java-io/src/test/java/com/baeldung/bufferedreader/BufferedReaderExampleUnitTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.bufferedreader;
+
+import org.junit.Test;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BufferedReaderExampleUnitTest {
+
+    private static final String FILE_PATH = "src/main/resources/input.txt";
+
+    @Test
+    public void givenBufferedReader_whenReadAllLines_thenReturnsContent() throws IOException {
+        BufferedReader reader = new BufferedReader(new FileReader(FILE_PATH));
+
+        BufferedReaderExample bre = new BufferedReaderExample();
+        String content = bre.readAllLines(reader);
+
+        assertThat(content).isNotEmpty();
+        assertThat(content).contains("Lorem ipsum");
+    }
+
+    @Test
+    public void givenBufferedReader_whenReadAllLinesWithStream_thenReturnsContent() throws IOException {
+        BufferedReader reader = new BufferedReader(new FileReader(FILE_PATH));
+
+        BufferedReaderExample bre = new BufferedReaderExample();
+        String content = bre.readAllLinesWithStream(reader);
+
+        assertThat(content).isNotEmpty();
+        assertThat(content).contains("Lorem ipsum");
+    }
+
+    @Test
+    public void whenReadFile_thenReturnsContent() {
+        BufferedReaderExample bre = new BufferedReaderExample();
+        String content = bre.readFile();
+
+        assertThat(content.toString()).contains("Lorem ipsum");
+    }
+
+    @Test
+    public void givenBufferedReader_whenReadAllCharsOneByOne_thenReturnsContent() throws IOException {
+        BufferedReader reader = new BufferedReader(new FileReader(FILE_PATH));
+
+        BufferedReaderExample bre = new BufferedReaderExample();
+        String content = bre.readAllCharsOneByOne(reader);
+
+        assertThat(content).isNotEmpty();
+        assertThat(content).contains("Lorem ipsum");
+    }
+
+    @Test
+    public void givenBufferedReader_whenReadMultipleChars_thenReturnsContent() throws IOException {
+        BufferedReader reader = new BufferedReader(new FileReader(FILE_PATH));
+
+        BufferedReaderExample bre = new BufferedReaderExample();
+        String content = bre.readMultipleChars(reader);
+
+        assertThat(content).isNotEmpty();
+        assertThat(content).isEqualTo("Lorem");
+    }
+
+    @Test
+    public void whenReadFileTryWithResources_thenReturnsContent() {
+        BufferedReaderExample bre = new BufferedReaderExample();
+        String content = bre.readFileTryWithResources();
+
+        assertThat(content.toString()).contains("Lorem ipsum");
+    }
+
+}

core-java-io/src/test/java/com/baeldung/bufferedreader/BufferedReaderUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.bufferedreader;
+
+import org.junit.Test;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.StringReader;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+public class BufferedReaderUnitTest {
+
+    private static final String FILE_PATH = "src/main/resources/input.txt";
+
+    @Test
+    public void givenBufferedReader_whenSkipUnderscores_thenOk() throws IOException {
+        StringBuilder result = new StringBuilder();
+
+        try (BufferedReader reader = new BufferedReader(new StringReader("1__2__3__4__5"))) {
+            int value;
+            while((value = reader.read()) != -1) {
+                result.append((char) value);
+                reader.skip(2L);
+            }
+        }
+
+        assertEquals("12345", result.toString());
+    }
+
+    @Test
+    public void givenBufferedReader_whenSkipsWhitespacesAtBeginning_thenOk() throws IOException {
+        String result;
+
+        try (BufferedReader reader = new BufferedReader(new StringReader("    Lorem ipsum dolor sit amet."))) {
+            do {
+                reader.mark(1);
+            } while(Character.isWhitespace(reader.read()));
+
+            reader.reset();
+            result = reader.readLine();
+        }
+
+        assertEquals("Lorem ipsum dolor sit amet.", result);
+    }
+
+    @Test
+    public void whenCreatesNewBufferedReader_thenOk() throws IOException {
+        try(BufferedReader reader = Files.newBufferedReader(Paths.get(FILE_PATH))) {
+            assertNotNull(reader);
+            assertTrue(reader.ready());
+        }
+    }
+
+}