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Merge pull request #48 from Doha2012/master 

add TestReader to test Read from file
This commit is contained in:
Eugen 2014-10-03 00:31:30 +03:00
parent f024fd8ebf d1bc7d22cc
commit a95196192e
1 changed files with 247 additions and 0 deletions
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core-java/src/test/java/org/baeldung/java/io/TestReader.java Normal file
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package org.baeldung.java.io;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.io.SequenceInputStream;
import java.io.StreamTokenizer;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Enumeration;
import java.util.Scanner;
import java.util.Vector;
import org.junit.Test;
/*
MappedByteBuffer
*/
public class TestReader {
@Test
public void whenReadWithBufferedReader_thenCorrect() throws IOException {
final String str = "Hello world";
final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
writer.write(str);
writer.close();
final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read.txt"));
final String currentLine = reader.readLine();
reader.close();
assertEquals(str, currentLine);
}
@Test
public void whenReadWithScanner_thenCorrect() throws IOException {
final String str = "Hello world 1 2,3,4";
final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
writer.write(str);
writer.close();
final Scanner scanner = new Scanner(new File("src/test/resources/test_read.txt"));
scanner.useDelimiter(" ");
assertTrue(scanner.hasNext());
assertEquals("Hello", scanner.next());
assertEquals("world", scanner.next());
assertEquals(1, scanner.nextInt());
scanner.useDelimiter(",| ");
assertTrue(scanner.hasNextInt());
assertEquals(2, scanner.nextInt());
assertEquals(3, scanner.nextInt());
assertEquals(4, scanner.nextInt());
scanner.close();
}
@Test
public void whenReadWithStreamTokenizer_thenCorrectTokens() throws IOException {
final String str = "Hello 1";
final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
writer.write(str);
writer.close();
final FileReader reader = new FileReader("src/test/resources/test_read.txt");
final StreamTokenizer tokenizer = new StreamTokenizer(reader);
tokenizer.nextToken();
assertEquals(StreamTokenizer.TT_WORD, tokenizer.ttype);
assertEquals("Hello", tokenizer.sval);
tokenizer.nextToken();
assertEquals(StreamTokenizer.TT_NUMBER, tokenizer.ttype);
assertEquals(1, tokenizer.nval, 0.0000001);
tokenizer.nextToken();
assertEquals(StreamTokenizer.TT_EOF, tokenizer.ttype);
reader.close();
}
@Test
public void whenReadWithDataInputStream_thenCorrect() throws IOException {
final String value = "Hello";
final DataOutputStream outStream = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("src/test/resources/test_read.txt")));
outStream.writeUTF(value);
outStream.close();
String result;
final DataInputStream reader = new DataInputStream(new FileInputStream("src/test/resources/test_read.txt"));
result = reader.readUTF();
reader.close();
assertEquals(value, result);
}
public void whenReadTwoFilesWithSequenceInputStream_thenCorrect() throws IOException {
final int value1 = 2000;
final int value2 = 5000;
FileOutputStream writer = new FileOutputStream("src/test/resources/test_read.txt");
writer.write(value1);
writer.close();
writer = new FileOutputStream("src/test/resources/test_read1.txt");
writer.write(value2);
writer.close();
final FileInputStream stream1 = new FileInputStream("src/test/resources/test_read.txt");
final FileInputStream stream2 = new FileInputStream("src/test/resources/test_read1.txt");
final SequenceInputStream sequence = new SequenceInputStream(stream1, stream2);
final DataInputStream reader = new DataInputStream(sequence);
assertEquals(value1, reader.readInt());
assertEquals(value2, reader.readInt());
reader.close();
stream2.close();
}
@Test
public void whenReadAllFilesInFolder_thenCorrect() throws IOException {
final File dir = new File("src/test/resources");
final File[] allFiles = dir.listFiles();
final int noOfFiles = allFiles.length;
final Vector<FileInputStream> allStreams = new Vector<FileInputStream>();
for (int i = 0; i < noOfFiles; i++) {
allStreams.add(new FileInputStream(allFiles[i]));
}
final Enumeration<FileInputStream> enu = allStreams.elements();
final SequenceInputStream sequence = new SequenceInputStream(enu);
final BufferedReader reader = new BufferedReader(new InputStreamReader(sequence));
String line = reader.readLine();
while (line != null) {
line = reader.readLine();
}
reader.close();
sequence.close();
}
@Test
public void whenReadUTFEncodedFile_thenCorrect() throws IOException {
final String str = "青空";
final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
writer.write(str);
writer.close();
final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/test/resources/test_read.txt"), "UTF-8"));
final String currentLine = reader.readLine();
reader.close();
assertEquals(str, currentLine);
}
@Test
public void whenReadFileContentsIntoString_thenCorrect() throws IOException {
final String str = "Hello world \n Test line \n";
final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
writer.write(str);
writer.close();
final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read.txt"));
final StringBuilder builder = new StringBuilder();
String currentLine = reader.readLine();
while (currentLine != null) {
builder.append(currentLine);
builder.append("\n");
currentLine = reader.readLine();
}
reader.close();
assertEquals(str, builder.toString());
}
@Test
public void whenReadWithFileChannel_thenCorrect() throws IOException {
final String str = "Hello world";
final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
writer.write(str);
writer.close();
final RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.txt", "r");
final FileChannel channel = reader.getChannel();
int bufferSize = 1024;
if (bufferSize > channel.size())
bufferSize = (int) channel.size();
final ByteBuffer buff = ByteBuffer.allocate(bufferSize);
channel.read(buff);
buff.flip();
assertEquals(str, new String(buff.array()));
channel.close();
reader.close();
}
@Test
public void whenReadSmallFileJava7_thenCorrect() throws IOException {
final String str = "Hello world";
final Path path = Paths.get("src/test/resources/test_read.txt");
final byte[] strToBytes = str.getBytes();
Files.write(path, strToBytes);
final String read = Files.readAllLines(path).get(0);
assertEquals(str, read);
}
@Test
public void whenReadLargeFileJava7_thenCorrect() throws IOException {
final String str = "Hello world";
final Path path = Paths.get("src/test/resources/test_read.txt");
final byte[] strToBytes = str.getBytes();
Files.write(path, strToBytes);
final BufferedReader reader = Files.newBufferedReader(path);
final String line = reader.readLine();
assertEquals(str, line);
}
}