Verify behavior of JVM.executeMain method

Author: JaroslavTulach

lib/java/os-environment/src/main/java/org/enso/os/environment/jni/JVM.java

@@ -40,7 +40,7 @@ public static JVM create(String javaHome, String... options) {
    * @param classNameWithSlashes class (with `/` as separators) to search main method in
    * @param args arguments to pass to the main method
    */
-  public void executeMain(String classNameWithSlashes, String[] args) {
+  public void executeMain(String classNameWithSlashes, String... args) {
     var e = env();
     try (var className = CTypeConversion.toCString(classNameWithSlashes);
         var mainName = CTypeConversion.toCString("main");

lib/java/os-environment/src/test/java/org/enso/os/environment/jni/LoadClassTest.java

@@ -1,5 +1,12 @@
 package org.enso.os.environment.jni;
 
+import java.io.File;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
@@ -10,11 +17,20 @@
 
 public class LoadClassTest {
   private static final String PATH = System.getProperty("java.home");
+  private static final URI JAR;
+  static {
+      try {
+          JAR = LoadClassTest.class.getProtectionDomain().getCodeSource().getLocation().toURI();
+      } catch (URISyntaxException ex) {
+          throw new IllegalStateException(ex);
+      }
+  }
   private static JVM jvm;
 
   private static JNI.JNIEnv env() {
     if (jvm == null) {
-      jvm = JVM.create(PATH, "-Dsay=Ahoj");
+      var cp = new File(JAR);
+      jvm = JVM.create(PATH, "-Dsay=Ahoj", "-Djava.class.path=" + cp);
     }
     return jvm.env();
   }
@@ -87,4 +103,13 @@ public void setSystemProperty() {
       strReleaseFn.call(env, res, chars);
     }
   }
+
+  @Test
+  public void executeMainClass() throws Exception {
+    var out = File.createTempFile("check-main", ".log");
+    jvm.executeMain("org/enso/os/environment/jni/TestMain", out.getPath());
+    var content = Files.readString(out.toPath());
+    assertEquals("Ciao", content);
+    out.delete();
+  }
 }

lib/java/os-environment/src/test/java/org/enso/os/environment/jni/TestMain.java

@@ -0,0 +1,16 @@
+package org.enso.os.environment.jni;
+
+import java.io.File;
+import java.io.FileWriter;
+
+public final class TestMain {
+    private TestMain() {
+    }
+
+    public static void main(String... args) throws Exception {
+        var out = new File(args[0]);
+        try (java.io.FileWriter os = new FileWriter(out)) {
+            os.write("Ciao");
+        }
+    }
+}