[JAVA-12757] Update code for OpenCSV article

libraries-data-io/src/test/java/com/baeldung/libraries/opencsv/OpenCsvIntegrationTest.java

@@ -1,66 +1,107 @@
 package com.baeldung.libraries.opencsv;
 
-import com.baeldung.libraries.opencsv.helpers.Helpers;
-import org.junit.After;
-import org.junit.Before;
+import com.baeldung.libraries.opencsv.beans.CsvBean;
 import org.junit.Test;
 
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
 public class OpenCsvIntegrationTest {
 
-    private Object testReadCsv(Object result) {
-        assert (result != null);
-        assert (result instanceof String);
-        assert (!((String) result).isEmpty());
-        System.out.println(result);
-        return result;
-    }
+    private static final String NEW_LINE = System.lineSeparator();
 
-    private Object testWriteCsv(Object result) {
-        assert (result instanceof String);
-        assert (!((String) result).isEmpty());
-        return result;
-    }
+    @Test
+    public void givenSampleData_whenReadUsingPosition_thenContentsRead() throws Exception {
+        List<CsvBean> values = Application.simpleSyncPositionBeanExample();
 
-    @Before
-    public void setup() {
+        assertThat(values)
+          .extracting(Object::toString)
+          .containsExactly(
+          "colA,colB",
+          "A,B",
+          "C,D",
+          "G,G",
+          "G,F"
+        );
     }
 
     @Test
-    public void positionExampleTest() {
-        testReadCsv(Application.simpleSyncPositionBeanExample());
+    public void givenSampleData_whenReadUsingNamedColumn_thenContentsRead() throws Exception {
+        List<CsvBean> values = Application.namedSyncColumnBeanExample();
+
+        assertThat(values)
+          .extracting(Object::toString)
+          .containsExactly(
+            "Joe,27",
+            "Jane,32",
+            "Bob,53"
+        );
     }
 
     @Test
-    public void namedColumnExampleTest() {
-        testReadCsv(Application.namedSyncColumnBeanExample());
+    public void givenSampleData_whenReadLineByLine_thenContentsRead() throws Exception {
+        List<String[]> lineByLineContents = Application.readLineByLineSyncExample();
+
+        assertThat(lineByLineContents)
+          .containsExactly(
+            new String[] {"colA", "colB"},
+            new String[] {"A", "B"},
+            new String[] {"C", "D"},
+            new String[] {"G", "G"},
+            new String[] {"G", "F"}
+          );
     }
 
     @Test
-    public void writeCsvUsingBeanBuilderTest() {
-        testWriteCsv(Application.writeSyncCsvFromBeanExample());
+    public void givenSampleData_whenReadAllLines_thenContentsRead() throws Exception {
+
+        List<String[]> contents = Application.readAllLinesSyncExample();
+
+        assertThat(contents)
+          .containsExactly(
+            new String[] {"colA", "colB"},
+            new String[] {"A", "B"},
+            new String[] {"C", "D"},
+            new String[] {"G", "G"},
+            new String[] {"G", "F"}
+          );
     }
 
     @Test
-    public void oneByOneExampleTest() {
-        testReadCsv(Application.oneByOneSyncExample());
+    public void givenSampleData_whenWriteCsvUsingBean_thenContentsWritten() throws Exception {
+        String contents = Application.writeSyncCsvFromBeanExample();
+
+        assertThat(contents.split(NEW_LINE))
+          .containsExactly(
+          "'colA','colB','colC'",
+          "'Test1','sample','data'",
+          "'Test2','ipso','facto'"
+        );
     }
 
     @Test
-    public void readAllExampleTest() {
-        testReadCsv(Application.readAllSyncExample());
+    public void givenSampleData_whenWriteCsvLineByLine_thenContentsWritten() throws Exception {
+        String contents = Application.writeLineByLineSyncExample();
+
+        assertThat(contents.split(NEW_LINE))
+          .containsExactly(
+            "\"ColA\",\"ColB\",\"ColC\",\"ColD\"",
+            "\"A\",\"B\",\"A\",\"B\"",
+            "\"BB\",\"AB\",\"AA\",\"B\""
+          );
     }
 
     @Test
-    public void csvWriterOneByOneTest() {
-        testWriteCsv(Application.csvWriterSyncOneByOne());
+    public void givenSampleData_whenWriteCsvAllLines_thenContentsWritten() throws Exception {
+        String contents = Application.writeAllLinesSyncExample();
+
+        assertThat(contents.split(NEW_LINE))
+          .containsExactly(
+            "\"ColA\",\"ColB\",\"ColC\",\"ColD\"",
+            "\"A\",\"B\",\"A\",\"B\"",
+            "\"BB\",\"AB\",\"AA\",\"B\""
+          );
     }
 
-    @Test
-    public void csvWriterAllTest() {
-        testWriteCsv(Application.csvWriterSyncAll());
-    }
-
-    @After
-    public void close() {
-    }
 }