Reformat header section

- Rename exceptions to be more descriptive
- Add tests for the FileSystemDB
- Add Mockito extension JUnit

pom.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
@@ -49,6 +49,12 @@
             <version>4.7.0</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <version>4.7.0</version>
+            <scope>test</scope>
+        </dependency>
         <!-- to test my json implementation -->
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>

src/main/java/de/hhhammer/playtime/ng/persistence/FileSystemDB.java

@@ -13,6 +13,7 @@ import java.util.Optional;
 import java.util.UUID;
 
 public final class FileSystemDB implements PersistPlayer, FindPlayer {
+
     private final File saveDirectory;
     private final SerializationFactory serializationFactory;
 
@@ -22,29 +23,32 @@ public final class FileSystemDB implements PersistPlayer, FindPlayer {
     }
 
     @Override
-    public void flush(final Player player) throws PersistException {
+    public void flush(final Player player) throws WritePlayerException {
         final var playerFile = new File(saveDirectory, player.uuid().toString());
+        final String serializedPlayer = serializationFactory.createSerializer(player).serialize();
         try (final var writer = new FileWriter(playerFile)) {
-            final String jsonPlayer = serializationFactory.createSerializer(player).serialize();
-            writer.write(jsonPlayer);
+            writer.write(serializedPlayer);
+            // ensure everything is written
             writer.flush();
         } catch (IOException e) {
-            throw new PersistException("Could not persist player data with id: " + player.uuid(), e);
+            throw new WritePlayerException("Could not persist player data from player: " + player.uuid(), e);
         }
     }
 
     @Override
-    public Optional<Player> findById(final UUID uuid) throws FindPlayerException {
+    public Optional<Player> findById(final UUID uuid) throws ReadPlayerException {
         final File[] files = getFiles();
         for (final var file : files) {
-            if (file.getName().equals(uuid.toString())) {
-                try {
-                    final String fileContent = Files.readString(file.toPath());
-                    final Player player = serializationFactory.createDeserializer(fileContent);
-                    return Optional.of(player);
-                } catch (IOException e) {
-                    throw new FindPlayerException("Player not found with the uuid: " + uuid, e);
-                }
+            if (!file.getName().equals(uuid.toString())) {
+                continue;
+            }
+
+            try {
+                final String fileContent = Files.readString(file.toPath());
+                final Player player = serializationFactory.createDeserializer(fileContent);
+                return Optional.of(player);
+            } catch (IOException e) {
+                throw new ReadPlayerException("Player not found with the uuid: " + uuid, e);
             }
         }
 
@@ -52,7 +56,7 @@ public final class FileSystemDB implements PersistPlayer, FindPlayer {
     }
 
     @Override
-    public Optional<Player> findByName(final String name) throws FindPlayerException {
+    public Optional<Player> findByName(final String name) throws ReadPlayerException {
         final File[] files = getFiles();
         for (final var file : files) {
             try {
@@ -62,7 +66,7 @@ public final class FileSystemDB implements PersistPlayer, FindPlayer {
                     return Optional.of(player);
                 }
             } catch (IOException e) {
-                throw new FindPlayerException("Player not found with the name: " + name, e);
+                throw new ReadPlayerException("Player not found with the name: " + name, e);
             }
         }
 
@@ -70,7 +74,7 @@ public final class FileSystemDB implements PersistPlayer, FindPlayer {
     }
 
     @Override
-    public List<Player> findAll() throws FindPlayerException {
+    public List<Player> findAll() throws ReadPlayerException {
         final File[] files = getFiles();
         final var playerList = new ArrayList<Player>();
         for (final var file : files) {
@@ -79,7 +83,7 @@ public final class FileSystemDB implements PersistPlayer, FindPlayer {
                 final Player player = serializationFactory.createDeserializer(fileContent);
                 playerList.add(player);
             } catch (IOException e) {
-                throw new FindPlayerException("Player not found with the path: " + file.getAbsolutePath(), e);
+                throw new ReadPlayerException("Player not found with the path: " + file.getAbsolutePath(), e);
             }
         }
 

src/main/java/de/hhhammer/playtime/ng/persistence/FindPlayer.java

@@ -7,9 +7,9 @@ import java.util.Optional;
 import java.util.UUID;
 
 public interface FindPlayer {
-    Optional<Player> findById(UUID uuid) throws FindPlayerException;
+    Optional<Player> findById(UUID uuid) throws ReadPlayerException;
 
-    Optional<Player> findByName(String name) throws FindPlayerException;
+    Optional<Player> findByName(String name) throws ReadPlayerException;
 
-    List<Player> findAll() throws FindPlayerException;
+    List<Player> findAll() throws ReadPlayerException;
 }

src/main/java/de/hhhammer/playtime/ng/persistence/FindPlayerException.java

@@ -1,11 +0,0 @@
-package de.hhhammer.playtime.ng.persistence;
-
-public final class FindPlayerException extends Exception {
-    public FindPlayerException(String msg) {
-        super(msg);
-    }
-
-    public FindPlayerException(final String message, final Throwable cause) {
-        super(message, cause);
-    }
-}

src/main/java/de/hhhammer/playtime/ng/persistence/PersistException.java

@@ -1,11 +0,0 @@
-package de.hhhammer.playtime.ng.persistence;
-
-import java.io.IOException;
-
-public final class PersistException extends Exception {
-
-    public PersistException(final String message, final IOException cause) {
-        super(message, cause);
-    }
-
-}

src/main/java/de/hhhammer/playtime/ng/persistence/PersistPlayer.java

@@ -3,5 +3,5 @@ package de.hhhammer.playtime.ng.persistence;
 import de.hhhammer.playtime.ng.player.Player;
 
 public interface PersistPlayer {
-    void flush(Player player) throws PersistException;
+    void flush(Player player) throws WritePlayerException;
 }

src/main/java/de/hhhammer/playtime/ng/persistence/ReadPlayerException.java

@@ -0,0 +1,11 @@
+package de.hhhammer.playtime.ng.persistence;
+
+public final class ReadPlayerException extends Exception {
+    public ReadPlayerException(String msg) {
+        super(msg);
+    }
+
+    public ReadPlayerException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/de/hhhammer/playtime/ng/persistence/WritePlayerException.java

@@ -0,0 +1,11 @@
+package de.hhhammer.playtime.ng.persistence;
+
+import java.io.IOException;
+
+public final class WritePlayerException extends Exception {
+
+    public WritePlayerException(final String message, final IOException cause) {
+        super(message, cause);
+    }
+
+}

src/test/java/de/hhhammer/playtime/ng/persistence/FileSystemDBTest.java

@@ -0,0 +1,229 @@
+package de.hhhammer.playtime.ng.persistence;
+
+import de.hhhammer.playtime.ng.player.Player;
+import de.hhhammer.playtime.ng.serialization.SerializationFactory;
+import de.hhhammer.playtime.ng.serialization.serializer.Serializer;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class FileSystemDBTest {
+
+    @Mock
+    private SerializationFactory mockSerializationFactory;
+    @Mock
+    private Player mockPlayer;
+    @Mock
+    private Serializer mockSerializer;
+    private File testDirectory;
+    private FileSystemDB fileSystemDB;
+
+    @BeforeEach
+    void setup() throws IOException {
+        final Path path = Files.createTempDirectory("playtime").toAbsolutePath();
+        this.testDirectory = path.toFile();
+        this.fileSystemDB = new FileSystemDB(testDirectory, mockSerializationFactory);
+    }
+
+    @AfterEach
+    void cleanup() {
+        testDirectory.delete();
+    }
+
+    @Nested
+    class FlushTest {
+
+        @Test
+        void shouldWriteFile() throws WritePlayerException {
+            when(mockSerializationFactory.createSerializer(any())).thenReturn(mockSerializer);
+            when(mockPlayer.uuid()).thenReturn(UUID.randomUUID());
+            when(mockSerializer.serialize()).thenReturn("");
+
+            assertEquals(0, testDirectory.listFiles().length);
+
+            fileSystemDB.flush(mockPlayer);
+
+            assertEquals(1, testDirectory.listFiles().length);
+        }
+
+        @Test
+        void shouldNameFileWithPlayerUUID() throws WritePlayerException {
+            final var uuid = UUID.randomUUID();
+            when(mockSerializationFactory.createSerializer(any())).thenReturn(mockSerializer);
+            when(mockPlayer.uuid()).thenReturn(uuid);
+            when(mockSerializer.serialize()).thenReturn("");
+
+            fileSystemDB.flush(mockPlayer);
+
+            final File[] foundFiles = testDirectory.listFiles();
+            assertEquals(1, foundFiles.length);
+            assertEquals(uuid.toString(), foundFiles[0].getName());
+        }
+
+        @Test
+        void shouldWriteContentFromSerializer() throws WritePlayerException, IOException {
+            when(mockSerializationFactory.createSerializer(any())).thenReturn(mockSerializer);
+            when(mockPlayer.uuid()).thenReturn(UUID.randomUUID());
+            final String content = "test content from serializer";
+            when(mockSerializer.serialize()).thenReturn(content);
+
+            fileSystemDB.flush(mockPlayer);
+
+            final File[] foundFiles = testDirectory.listFiles();
+            assertEquals(1, foundFiles.length);
+            final String foundContent = Files.readString(foundFiles[0].toPath());
+            assertEquals(content, foundContent);
+        }
+    }
+
+    @Nested
+    class FindById {
+
+        @Test
+        void shouldThrowIfDirectoryIsAFile() {
+            final var notADir = new File(testDirectory, "not_a_dir");
+            final var fileSystemDB = new FileSystemDB(notADir, mockSerializationFactory);
+            final Exception exception = assertThrows(RuntimeException.class, () -> fileSystemDB.findById(UUID.randomUUID()));
+            assertEquals("Could not find files in: " + notADir.getAbsolutePath(), exception.getMessage());
+        }
+
+        @Test
+        void shouldBeEmptyIfNoFileIsPresent() throws IOException, ReadPlayerException {
+            assertEquals(0, testDirectory.listFiles().length);
+
+            final Optional<Player> foundPlayer = fileSystemDB.findById(UUID.randomUUID());
+
+            assertTrue(foundPlayer.isEmpty());
+        }
+
+        @Test
+        void shouldBeEmptyIfUuidNotFound() throws IOException, ReadPlayerException {
+            new File(testDirectory, "not_a_uuid").createNewFile();
+
+            final Optional<Player> foundPlayer = fileSystemDB.findById(UUID.randomUUID());
+
+            assertTrue(foundPlayer.isEmpty());
+        }
+
+        @Test
+        void shouldDeserializeFileContent() throws IOException, ReadPlayerException {
+            final var playerUUID = UUID.randomUUID();
+            final var fakePlayerFile = new File(testDirectory, playerUUID.toString());
+            final String fileContent = "test content";
+            Files.write(fakePlayerFile.toPath(), fileContent.getBytes());
+
+            when(mockSerializationFactory.createDeserializer(any())).thenReturn(mockPlayer);
+
+            fileSystemDB.findById(playerUUID);
+
+            verify(mockSerializationFactory).createDeserializer(fileContent);
+        }
+    }
+
+    @Nested
+    class FindByName {
+
+        @Test
+        void shouldBeEmptyIfNoFilesExist() throws ReadPlayerException {
+            final Optional<Player> result = fileSystemDB.findByName("username");
+            assertTrue(result.isEmpty());
+        }
+
+        @Test
+        void shouldFindThroughDeserializePlayerWithOnlyOneFile() throws IOException, ReadPlayerException {
+            final var username = "username";
+            when(mockPlayer.name()).thenReturn(username);
+            final var fakePlayerFile = new File(testDirectory, "fake_player_file");
+            Files.write(fakePlayerFile.toPath(), "".getBytes());
+            when(mockSerializationFactory.createDeserializer(anyString())).thenReturn(mockPlayer);
+
+            final Optional<Player> result = fileSystemDB.findByName(username);
+            assertTrue(result.isPresent());
+        }
+
+        @Test
+        void shouldNotFindThroughDeserializePlayerWithOnlyOneFile() throws IOException, ReadPlayerException {
+            final var username = "username";
+            when(mockPlayer.name()).thenReturn(username);
+            final var fakePlayerFile = new File(testDirectory, "fake_player_file");
+            Files.write(fakePlayerFile.toPath(), "".getBytes());
+            when(mockSerializationFactory.createDeserializer(anyString())).thenReturn(mockPlayer);
+
+            final Optional<Player> result = fileSystemDB.findByName("not_a_username");
+            assertTrue(result.isEmpty());
+        }
+
+        @Test
+        void shouldFindThroughDeserializePlayerOnMultipleFiles() throws IOException, ReadPlayerException {
+            final var wantedUsername = "username";
+            final var notWantedUsername = "not_wanted_username";
+            final var rightPlayer = mock(Player.class);
+            final var wrongPlayer = mock(Player.class);
+            when(rightPlayer.name()).thenReturn(wantedUsername);
+            when(wrongPlayer.name()).thenReturn(notWantedUsername);
+            final var rightPlayerFileContent = "right";
+            final var wrongPlayerFileContent = "wrong";
+            final var rightPlayerFile = new File(testDirectory, "right_player_file");
+            final var wrongPlayerFile = new File(testDirectory, "wrong_player_file");
+            Files.write(rightPlayerFile.toPath(), rightPlayerFileContent.getBytes());
+            Files.write(wrongPlayerFile.toPath(), wrongPlayerFileContent.getBytes());
+            when(mockSerializationFactory.createDeserializer(rightPlayerFileContent)).thenReturn(rightPlayer);
+            when(mockSerializationFactory.createDeserializer(wrongPlayerFileContent)).thenReturn(wrongPlayer);
+
+            final Optional<Player> result = fileSystemDB.findByName(wantedUsername);
+            assertTrue(result.isPresent());
+        }
+    }
+
+    @Nested
+    class FindAllTest {
+
+        @Test
+        void shouldBeEmptyIfNoFilesExist() throws ReadPlayerException {
+            final List<Player> result = fileSystemDB.findAll();
+            assertEquals(0, result.size());
+        }
+
+        @Test
+        void shouldFindOneFile() throws IOException, ReadPlayerException {
+            final var fakePlayerFile = new File(testDirectory, "fake_player_file");
+            Files.write(fakePlayerFile.toPath(), "test content".getBytes());
+            when(mockSerializationFactory.createDeserializer(anyString())).thenReturn(mockPlayer);
+
+            final List<Player> result = fileSystemDB.findAll();
+            assertEquals(1, result.size());
+        }
+
+        @Test
+        void shouldFindTwoFile() throws IOException, ReadPlayerException {
+            final var fakePlayerFile = new File(testDirectory, "fake_player_file");
+            Files.write(fakePlayerFile.toPath(), "test content".getBytes());
+            final var fakePlayerFile2 = new File(testDirectory, "fake_player_file_2");
+            Files.write(fakePlayerFile2.toPath(), "test content".getBytes());
+
+            when(mockSerializationFactory.createDeserializer(anyString())).thenReturn(mockPlayer);
+
+            final List<Player> result = fileSystemDB.findAll();
+            assertEquals(2, result.size());
+        }
+    }
+
+}