Added Java Process unit test

core-java/src/test/java/org/baeldung/java/shell/JavaProcessUnitTest.java

@@ -0,0 +1,67 @@
+package org.baeldung.java.shell;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.*;
+import java.util.concurrent.Executors;
+import java.util.function.Consumer;
+
+public class JavaProcessUnitTest {
+    private static final boolean IS_WINDOWS = System.getProperty("os.name").toLowerCase().startsWith("windows");
+
+    private static class StreamGobbler implements Runnable {
+        private InputStream inputStream;
+        private Consumer<String> consumer;
+
+        public StreamGobbler(InputStream inputStream, Consumer<String> consumer) {
+            this.inputStream = inputStream;
+            this.consumer = consumer;
+        }
+
+        @Override
+        public void run() {
+            new BufferedReader(new InputStreamReader(inputStream)).lines().forEach(consumer);
+        }
+    }
+
+    private Consumer<String> consumer = new Consumer<String>() {
+        @Override
+        public void accept(String s) {
+            Assert.assertNotNull(s);
+        }
+    };
+
+    private String homeDirectory = System.getProperty("user.home");
+
+    @Test
+    public void givenProcess_whenCreatingViaRuntime_shouldSucceed() throws Exception {
+        Process process;
+        if (IS_WINDOWS) {
+            process = Runtime.getRuntime().exec(String.format("cmd.exe /c dir %s", homeDirectory));
+        } else {
+            process = Runtime.getRuntime().exec(String.format("sh -c ls %s", homeDirectory));
+        }
+        StreamGobbler streamGobbler = new StreamGobbler(process.getInputStream(), consumer);
+        Executors.newSingleThreadExecutor().submit(streamGobbler);
+        int exitCode = process.waitFor();
+        Assert.assertEquals(0, exitCode);
+    }
+
+    @Test
+    public void givenProcess_whenCreatingViaProcessBuilder_shouldSucceed() throws Exception {
+        ProcessBuilder builder = new ProcessBuilder();
+        if (IS_WINDOWS) {
+            builder.command("cmd.exe", "/c", "dir");
+            builder.inheritIO();
+        } else {
+            builder.command("sh", "-c", "ls");
+        }
+        builder.directory(new File(homeDirectory));
+        Process process = builder.start();
+        StreamGobbler streamGobbler = new StreamGobbler(process.getInputStream(), consumer);
+        Executors.newSingleThreadExecutor().submit(streamGobbler);
+        int exitCode = process.waitFor();
+        Assert.assertEquals(0, exitCode);
+    }
+}