Add test cases for ByteStreamFileWriter

Author: cboehme

metafacture-io/build.gradle

@@ -25,4 +25,5 @@ dependencies {
   runtimeOnly 'org.tukaani:xz:1.6'
   testImplementation 'junit:junit:4.12'
   testImplementation 'org.mockito:mockito-core:2.5.5'
+  testImplementation 'org.assertj:assertj-core:3.11.1'
 }

metafacture-io/src/test/java/org/metafacture/io/ByteStreamFileWriterTest.java

@@ -0,0 +1,102 @@
+package org.metafacture.io;
+
+import static java.util.Arrays.asList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.contentOf;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+public class ByteStreamFileWriterTest {
+
+    private ByteStreamFileWriter byteStreamFileWriter;
+
+    @Before
+    public void setupSystemUnderTest() {
+
+        byteStreamFileWriter = new ByteStreamFileWriter();
+    }
+
+    @Test
+    public void shouldWriteBytesToFile() throws IOException {
+
+        File outputFile = tempFolder.newFile();
+        byteStreamFileWriter.setFileNameSupplier(() -> outputFile);
+
+        byteStreamFileWriter.process(SOME_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.closeStream();
+
+        assertThat(outputFile).isFile();
+        assertThat(contentOf(outputFile)).isEqualTo(SOME_DATA);
+    }
+
+    @Test
+    public void shouldStartNewOutputFileOnResetStreamEvent() throws IOException {
+
+        List<File> outputFiles = asList(
+                tempFolder.newFile(),
+                tempFolder.newFile());
+        byteStreamFileWriter.setFileNameSupplier(outputFiles.iterator()::next);
+
+        byteStreamFileWriter.process(SOME_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.resetStream();
+        byteStreamFileWriter.process(SOME_MORE_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.closeStream();
+
+        assertThat(outputFiles.get(0)).isFile();
+        assertThat(contentOf(outputFiles.get(0))).isEqualTo(SOME_DATA);
+        assertThat(outputFiles.get(1)).isFile();
+        assertThat(contentOf(outputFiles.get(1))).isEqualTo(SOME_MORE_DATA);
+    }
+
+    @Test
+    public void shouldOverwriteExistingFilesByDefault() throws IOException {
+
+        File outputFile = tempFolder.newFile();
+        byteStreamFileWriter.setFileNameSupplier(() -> outputFile);
+
+        byteStreamFileWriter.process(SOME_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.resetStream();
+        byteStreamFileWriter.process(SOME_MORE_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.closeStream();
+
+        assertThat(outputFile).isFile();
+        assertThat(contentOf(outputFile)).isEqualTo(SOME_MORE_DATA);
+    }
+
+    @Test
+    public void shouldAppendIfParameterAppendIfFileExistsIsSet() throws IOException {
+
+
+        File outputFile = tempFolder.newFile();
+        byteStreamFileWriter.setFileNameSupplier(() -> outputFile);
+        byteStreamFileWriter.setAppendIfFileExists(true);
+
+        byteStreamFileWriter.process(SOME_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.resetStream();
+        byteStreamFileWriter.process(SOME_MORE_DATA.getBytes(StandardCharsets.UTF_8));
+        byteStreamFileWriter.closeStream();
+
+        assertThat(outputFile).isFile();
+        assertThat(contentOf(outputFile)).isEqualTo(SOME_DATA + SOME_MORE_DATA);
+    }
+
+    private static final String SOME_DATA = "Nil desperandum";
+    private static final String SOME_MORE_DATA = "De omnibus dubitandum";
+
+    @Rule
+    public TemporaryFolder tempFolder = new TemporaryFolder();
+
+    @Rule
+    public MockitoRule mockitoRule = MockitoJUnit.rule();
+
+}