BAEL-1829 - Overview of Apache Crunch

libraries-data/src/test/java/com/baeldung/crunch/MemPipelineUnitTest.java

@@ -0,0 +1,89 @@
+package com.baeldung.crunch;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Calendar;
+
+import org.apache.crunch.PCollection;
+import org.apache.crunch.Pipeline;
+import org.apache.crunch.Source;
+import org.apache.crunch.Target;
+import org.apache.crunch.impl.mem.MemPipeline;
+import org.apache.crunch.io.From;
+import org.apache.crunch.io.To;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class MemPipelineUnitTest {
+
+    private static final String INPUT_FILE_PATH = "src/test/resources/crunch/input.txt";
+
+    @Test
+    public void givenPipeLineAndSource_whenSourceRead_thenExpectedNumberOfRecordsRead() {
+        Pipeline pipeline = MemPipeline.getInstance();
+        Source<String> source = From.textFile(INPUT_FILE_PATH);
+
+        PCollection<String> lines = pipeline.read(source);
+
+        assertEquals(21, lines.asCollection()
+            .getValue()
+            .size());
+    }
+
+    @Test
+    public void givenPipeLine_whenTextFileRead_thenExpectedNumberOfRecordsRead() {
+        Pipeline pipeline = MemPipeline.getInstance();
+
+        PCollection<String> lines = pipeline.readTextFile(INPUT_FILE_PATH);
+
+        assertEquals(21, lines.asCollection()
+            .getValue()
+            .size());
+    }
+
+    private String createOutputPath() throws IOException {
+        Path path = Files.createTempDirectory("test");
+        final String outputFilePath = path.toString() + File.separatorChar
+            + "output.text";
+        return outputFilePath;
+    }
+
+    @Test
+    @Ignore("Requires Hadoop binaries")
+    public void givenCollection_whenWriteCalled_fileWrittenSuccessfully()
+        throws IOException {
+        PCollection<String> inputStrings = MemPipeline.collectionOf("Hello",
+            "Apache", "Crunch", Calendar.getInstance()
+                .toString());
+        final String outputFilePath = createOutputPath();
+        Target target = To.textFile(outputFilePath);
+
+        inputStrings.write(target);
+
+        Pipeline pipeline = MemPipeline.getInstance();
+        PCollection<String> lines = pipeline.readTextFile(outputFilePath);
+        assertIterableEquals(inputStrings.materialize(), lines.materialize());
+    }
+
+    @Test
+    @Ignore("Requires Hadoop binaries")
+    public void givenPipeLine_whenWriteTextFileCalled_fileWrittenSuccessfully()
+        throws IOException {
+        Pipeline pipeline = MemPipeline.getInstance();
+        PCollection<String> inputStrings = MemPipeline.collectionOf("Hello",
+            "Apache", "Crunch", Calendar.getInstance()
+                .toString());
+        final String outputFilePath = createOutputPath();
+
+        pipeline.writeTextFile(inputStrings, outputFilePath);
+
+        PCollection<String> lines = pipeline.readTextFile(outputFilePath);
+        assertIterableEquals(inputStrings.materialize(), lines.materialize());
+    }
+
+}