diff --git a/core-java-modules/core-java-io-3/src/test/java/com/baeldung/linenumber/LineAtGivenNumberUnitTest.java b/core-java-modules/core-java-io-3/src/test/java/com/baeldung/linenumber/LineAtGivenNumberUnitTest.java new file mode 100644 index 0000000000..ffe3221d62 --- /dev/null +++ b/core-java-modules/core-java-io-3/src/test/java/com/baeldung/linenumber/LineAtGivenNumberUnitTest.java @@ -0,0 +1,82 @@ +package com.baeldung.linenumber; + +import org.apache.commons.io.FileUtils; +import org.apache.commons.io.IOUtils; +import org.junit.Test; + +import java.io.BufferedReader; +import java.io.File; +import java.io.FileInputStream; +import java.io.IOException; +import java.nio.charset.StandardCharsets; +import java.nio.file.Files; +import java.nio.file.Paths; +import java.util.List; +import java.util.Scanner; +import java.util.stream.Stream; + +import static org.junit.Assert.assertEquals; + +public class LineAtGivenNumberUnitTest { + + private static final String FILE_PATH = "src/test/resources/linesInput.txt"; + + @Test + public void givenFile_whenUsingBufferedReader_thenExtractedLineIsCorrect() throws IOException { + try (BufferedReader br = Files.newBufferedReader(Paths.get(FILE_PATH))) { + for (int i = 0; i < 3; i++) { + br.readLine(); + } + + String extractedLine = br.readLine(); + assertEquals("Line 4", extractedLine); + } + } + + @Test + public void givenFile_whenUsingScanner_thenExtractedLineIsCorrect() throws IOException { + try (Scanner scanner = new Scanner(new File(FILE_PATH))) { + for (int i = 0; i < 3; i++) { + scanner.nextLine(); + } + + String extractedLine = scanner.nextLine(); + assertEquals("Line 4", extractedLine); + } + } + + @Test + public void givenSmallFile_whenUsingFilesAPI_thenExtractedLineIsCorrect() throws IOException { + String extractedLine = Files.readAllLines(Paths.get(FILE_PATH)).get(4); + + assertEquals("Line 5", extractedLine); + } + + @Test + public void givenLargeFile_whenUsingFilesAPI_thenExtractedLineIsCorrect() throws IOException { + try (Stream lines = Files.lines(Paths.get(FILE_PATH))) { + String extractedLine = lines.skip(4).findFirst().get(); + + assertEquals("Line 5", extractedLine); + } + } + + @Test + public void givenFile_whenUsingFileUtils_thenExtractedLineIsCorrect() throws IOException { + ClassLoader classLoader = getClass().getClassLoader(); + File file = new File(classLoader.getResource("linesInput.txt").getFile()); + + List lines = FileUtils.readLines(file, "UTF-8"); + + String extractedLine = lines.get(0); + assertEquals("Line 1", extractedLine); + } + + @Test + public void givenFile_whenUsingIOUtils_thenExtractedLineIsCorrect() throws IOException { + String fileContent = IOUtils.toString(new FileInputStream(FILE_PATH), StandardCharsets.UTF_8); + + String extractedLine = fileContent.split(System.lineSeparator())[0]; + assertEquals("Line 1", extractedLine); + } +} diff --git a/core-java-modules/core-java-io-3/src/test/resources/linesInput.txt b/core-java-modules/core-java-io-3/src/test/resources/linesInput.txt new file mode 100644 index 0000000000..572d5d9483 --- /dev/null +++ b/core-java-modules/core-java-io-3/src/test/resources/linesInput.txt @@ -0,0 +1,5 @@ +Line 1 +Line 2 +Line 3 +Line 4 +Line 5