add predictor Example tests

scala-package/examples/pom.xml

@@ -15,6 +15,7 @@
 
   <properties>
     <skipTests>true</skipTests>
+    <skipJavaTests>${skipTests}</skipJavaTests>
   </properties>
 
   <build>
@@ -128,5 +129,11 @@
       <artifactId>slf4j-simple</artifactId>
       <version>1.7.5</version>
     </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.11</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 </project>

scala-package/examples/src/main/scala/org/apache/mxnetexamples/Util.scala

@@ -24,9 +24,9 @@ import org.apache.commons.io.FileUtils
 
 object Util {
 
-  def downloadUrl(url: String, filePath: String, maxRetry: Option[Int] = None) : Unit = {
+  def downloadUrl(url: String, filePath: String, maxRetry: Int = 3) : Unit = {
     val tmpFile = new File(filePath)
-    var retry = maxRetry.getOrElse(3)
+    var retry = maxRetry
     var success = false
     if (!tmpFile.exists()) {
       while (retry > 0 && !success) {

scala-package/examples/src/test/java/org/apache/mxnetexamples/javaapi/infer/predictor/PredictorExampleSuite.java

@@ -0,0 +1,50 @@
+package org.apache.mxnetexamples.javaapi.infer.predictor;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.apache.mxnetexamples.Util;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+
+public class PredictorExampleSuite {
+
+    final static Logger logger = LoggerFactory.getLogger(PredictorExampleSuite.class);
+    private static String modelPathPrefix = "";
+    private static String inputImagePath = "";
+
+    @BeforeClass
+    public static void downloadFile() {
+        logger.info("Downloading resnet-18 model");
+
+        String tempDirPath = System.getProperty("java.io.tmpdir");
+        logger.info("tempDirPath: %s".format(tempDirPath));
+
+        String baseUrl = "https://s3.us-east-2.amazonaws.com/scala-infer-models";
+
+        Util.downloadUrl(baseUrl + "/resnet-18/resnet-18-symbol.json",
+                tempDirPath + "/resnet18/resnet-18-symbol.json", 3);
+        Util.downloadUrl(baseUrl + "/resnet-18/resnet-18-0000.params",
+                tempDirPath + "/resnet18/resnet-18-0000.params", 3);
+        Util.downloadUrl(baseUrl + "/resnet-18/synset.txt",
+                tempDirPath + "/resnet18/synset.txt", 3);
+        Util.downloadUrl("https://s3.amazonaws.com/model-server/inputs/Pug-Cookie.jpg",
+                tempDirPath + "/inputImages/resnet18/Pug-Cookie.jpg", 3);
+
+        modelPathPrefix = tempDirPath + File.separator + "resnet18/resnet-18";
+        inputImagePath = tempDirPath + File.separator +
+                "inputImages/resnet18/Pug-Cookie.jpg";
+    }
+
+    @Test
+    public void testPredictor(){
+        PredictorExample example = new PredictorExample();
+        String[] args = new String[]{
+                "--model-path-prefix", modelPathPrefix,
+                "--input-image", inputImagePath
+        };
+        example.main(args);
+    }
+
+}