Issue #2 - Added a few unit tests for the FileStorage

pom.xml

@@ -34,13 +34,28 @@
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<maven.compiler.target>1.8</maven.compiler.target>
 		<maven.compiler.source>1.8</maven.compiler.source>
+		<junit-jupiter-api.version>5.7.0</junit-jupiter-api.version>
+		<hamcrest.version>2.2</hamcrest.version>
 	</properties>
 	<modules>
 		<module>shielddb-core</module>
 		<module>shielddb-demo-app</module>
 		<module>shielddb-gson-backend</module>
 	</modules>
-
+  <dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>org.junit.jupiter</groupId>
+				<artifactId>junit-jupiter-api</artifactId>
+				<version>${junit-jupiter-api.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>org.hamcrest</groupId>
+				<artifactId>hamcrest</artifactId>
+				<version>${hamcrest.version}</version>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
 	<distributionManagement>
 		<snapshotRepository>
 			<id>ossrh</id>
@@ -108,6 +123,11 @@
 					<autoReleaseAfterClose>true</autoReleaseAfterClose>
 				</configuration>
 			</plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0-M5</version>
+      </plugin>
 		</plugins>
 	</build>
 </project>

shielddb-core/pom.xml

@@ -1,9 +1,23 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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>
-  <parent>
-    <groupId>nf.fr.k49</groupId>
-    <artifactId>shielddb-parent</artifactId>
-    <version>0.1.2-SNAPSHOT</version>
-  </parent>
-  <artifactId>shielddb-core</artifactId>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	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>
+	<parent>
+		<groupId>nf.fr.k49</groupId>
+		<artifactId>shielddb-parent</artifactId>
+		<version>0.1.2-SNAPSHOT</version>
+	</parent>
+	<artifactId>shielddb-core</artifactId>
+	<dependencies>
+		<dependency>
+			<groupId>org.junit.jupiter</groupId>
+			<artifactId>junit-jupiter-api</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.hamcrest</groupId>
+			<artifactId>hamcrest</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
 </project>

shielddb-core/src/test/java/nf/fr/k49/shielddb/core/storage/FileStorageTest.java

@@ -0,0 +1,112 @@
+package nf.fr.k49.shielddb.core.storage;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.fail;
+import static org.hamcrest.MatcherAssert.*;
+import static org.hamcrest.CoreMatchers.*;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileVisitOption;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.UUID;
+import java.util.stream.Collector;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.MethodOrderer;
+import org.junit.jupiter.api.Order;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestMethodOrder;
+
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+class FileStorageTest {
+
+	static Path testWorkDir;
+
+	@BeforeAll
+	static void setUpBeforeClass() throws Exception {
+		testWorkDir = Files.createTempDirectory(FileStorageTest.class.getSimpleName());
+	}
+
+	@AfterAll
+	static void tearDownAfterClass() throws Exception {
+		Files.walk(testWorkDir).map(Path::toFile).forEach(File::delete);
+	}
+
+
+	private Path createFilePathForTest() {
+		return Paths.get(testWorkDir.toString(), UUID.randomUUID().toString());
+	}
+
+	private String getExistentFilePathForTest() throws IOException {
+		return Files.write(createFilePathForTest(), UUID.randomUUID().toString().getBytes(Charset.defaultCharset()))
+				.toString();
+	}
+
+	private String getExistentFilePathForTest(Charset charset) throws IOException {
+		return Files.write(createFilePathForTest(), UUID.randomUUID().toString().getBytes(charset)).toString();
+	}
+
+	@Test
+	@Order(0)
+	final void testFileStorageString() throws IOException {
+		String existentFilePath = getExistentFilePathForTest();
+		assertDoesNotThrow(() -> {
+			new FileStorage(existentFilePath);
+		}, "must be able to be instantiated when it's passed as arguments a valid and existent file path");
+	}
+
+	@Test
+	@Order(1)
+	final void testFileStorageStringCharset() throws IOException {
+		String targetFilePath = getExistentFilePathForTest(StandardCharsets.ISO_8859_1);
+		assertDoesNotThrow(() -> {
+			new FileStorage(targetFilePath, StandardCharsets.ISO_8859_1);
+		}, "must be able to be instantiated when it's passed as arguments a valid and existent file path and a valid charset");
+	}
+
+	@Test
+	@Order(2)
+	final void testRead() throws IOException {
+		String targetFilePath = getExistentFilePathForTest(StandardCharsets.UTF_8);
+		String expectedContent = Files.readAllLines(Paths.get(targetFilePath), StandardCharsets.UTF_8)
+				.stream().collect(Collectors.joining(""));
+		FileStorage fileStorage = new FileStorage(targetFilePath, StandardCharsets.UTF_8);
+		String actualContent = fileStorage.read();
+		assertThat("the read method does not working as expected: unexpected retrieved content", actualContent,
+				equalTo(expectedContent));
+	}
+
+	@Test
+	@Order(3)
+	final void testWrite() throws IOException {
+		String targetFilePath = getExistentFilePathForTest(StandardCharsets.UTF_8);
+		FileStorage fileStorage = new FileStorage(targetFilePath, StandardCharsets.UTF_8);
+		String expectedContent = UUID.randomUUID().toString();
+		fileStorage.write(expectedContent);
+		String actualContent = Files.readAllLines(Paths.get(targetFilePath), StandardCharsets.UTF_8).stream()
+				.collect(Collectors.joining(""));
+		assertThat("the write method does not working as expected: unexpected content has been wrote", expectedContent,
+				equalTo(actualContent));
+	}
+
+	@Test
+	@Order(4)
+	final void testClear() throws IOException {
+		String targetFilePath = getExistentFilePathForTest(StandardCharsets.UTF_8);
+		FileStorage fileStorage = new FileStorage(targetFilePath, StandardCharsets.UTF_8);
+		String expectedContent = "";
+		fileStorage.clear();
+		String actualContent = Files.readAllLines(Paths.get(targetFilePath), StandardCharsets.UTF_8).stream()
+				.collect(Collectors.joining(""));
+		assertThat("the clear method does not working as expected: the retrieved content wasn't cleaned", expectedContent,
+				equalTo(actualContent));
+	}
+
+}