Im trying to unit test my overwriting method that overwrites the file (or create new one if given file does not exists). My idea was to compare two arrays before overwriting and after overwriting, so I made it, but unfortunately, it says that actual array is null. I am using TemporaryFolder so that it can be easily deleted after test.
Method I want to unit test + method that is needed to test overwrite method.
package rankingsystem;
import contentfile.ContentFileRetriever;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.*;
import java.util.stream.Collectors;
public class RankingSystemService {
private ContentFileRetriever contentFileRetriever;
public RankingSystemService(ContentFileRetriever contentFileRetriever) {
this.contentFileRetriever = contentFileRetriever;
}
...
String[] retrieveRankingData(String rankingPathFile) {
return contentFileRetriever.getContent(rankingPathFile);
}
void overwriteFileWithGivenResult(String name, long timeOfFinishingGame, String rankingPathFile) {
try (FileWriter writer = new FileWriter(rankingPathFile, true);
BufferedWriter bufferedWriter = new BufferedWriter(writer)) {
bufferedWriter.write(name + " " + timeOfFinishingGame);
bufferedWriter.newLine();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Test:
public class RankingSystemServiceTest {
@Rule
public TemporaryFolder tempFolder = new TemporaryFolder();
@Mock
ContentFileRetriever contentFileRetriever;
private RankingSystemService rankingSystemService = new RankingSystemService(contentFileRetriever);
@Before
public void setup() {
MockitoAnnotations.initMocks(this);
rankingSystemService = new RankingSystemService(contentFileRetriever);
}
@Test
public void overwriteFileWithGivenResult() throws IOException {
File rankingFile = tempFolder.newFile("rankingText.txt");
String rankingFilePath = rankingFile.getPath();
String[] actualResultBeforeOverwriting = rankingSystemService.retrieveRankingData(rankingFilePath);
String[] expectedResultBeforeOverwriting = {};
assertArrayEquals(expectedResultBeforeOverwriting, actualResultBeforeOverwriting);
rankingSystemService.overwriteFileWithGivenResult("Piotr", 1L, rankingFilePath);
String[] afterOverwriting = rankingSystemService.retrieveRankingData(rankingFilePath);
String[] expectedResultAfterOverwriting = {"Piotr 1"};
assertArrayEquals(expectedResultAfterOverwriting, afterOverwriting);
}
getContent which retrieve content:
@Override
public String[] getContent(String pathName) {
try (Stream<String> contentFileStream = Files.lines(Paths.get(pathName))) {
return contentFileStream.toArray(String[]::new);
} catch (IOException e) {
throw new IllegalArgumentException(e);
}
}
Stacktrace:
java.lang.AssertionError: actual array was null
at org.junit.Assert.fail(Assert.java:88)
at org.junit.internal.ComparisonCriteria.assertArraysAreSameLength(ComparisonCriteria.java:71)
at org.junit.internal.ComparisonCriteria.arrayEquals(ComparisonCriteria.java:37)
at org.junit.Assert.internalArrayEquals(Assert.java:532)
at org.junit.Assert.assertArrayEquals(Assert.java:283)
at org.junit.Assert.assertArrayEquals(Assert.java:298)
at rankingsystem.RankingSystemServiceTest.overwriteFileWithGivenResult(RankingSystemServiceTest.java:61)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
