[streaming] TestDataUtilTest added to test the download function of TestDataUtil

flink-addons/flink-streaming/src/test/java/eu/stratosphere/streaming/util/TestDataUtilTest.java

+package eu.stratosphere.streaming.util;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import org.junit.Test;
+
+public class TestDataUtilTest {
+
+	@Test
+	public void testDownload() throws FileNotFoundException, IOException {
+		String fileToDownload = "hamlet.txt";
+		String expectedFile = "hamletTestExpectation.txt";
+
+		deleteFile(TestDataUtil.testDataDir + fileToDownload);
+		
+		TestDataUtil.download(fileToDownload);
+
+		assertTrue(compareFile(TestDataUtil.testDataDir + expectedFile, TestDataUtil.testDataDir
+				+ fileToDownload));
+	}
+
+	public void deleteFile(String fileLocation) throws IOException{
+		Path path = Paths.get(fileLocation);
+		if(Files.exists(path))
+			Files.delete(path);
+	}
+
+	public boolean compareFile(String file1, String file2) throws FileNotFoundException,
+			IOException {
+
+		BufferedReader myInput1 = new BufferedReader(new InputStreamReader(new FileInputStream(file1)));
+		BufferedReader myInput2 = new BufferedReader(new InputStreamReader(new FileInputStream(file2)));
+
+		String line1, line2;
+		while ((line1 = myInput1.readLine()) != null && (line2 = myInput2.readLine()) != null) {
+			if (!line1.equals(line2))
+				return false;
+		}
+		return true;
+	}
+}
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