Add Java 10 test class ...

src/test/java/pl/mperor/lab/java/Java10.java

@@ -0,0 +1,41 @@
+package pl.mperor.lab.java;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+/**
+ * Java 10 (March 2018)
+ */
+public class Java10 {
+
+    @Test
+    public void testLocalVariableTypeInferenceKeywordAkaVar() {
+        var message = "Hello Java 10!";
+        // same as String message = ...
+        Assertions.assertEquals("Hello Java 10!", message);
+
+        var number = 10;
+        // same as int number = ...
+        Assertions.assertEquals(10, number);
+    }
+
+    @Test
+    public void testCopyOf() {
+        var original = List.of("Java", "Python", "JavaScript");
+        var copy = List.copyOf(original);
+        Assertions.assertEquals(original, copy);
+        Assertions.assertThrows(UnsupportedOperationException.class, () -> copy.add("Ruby"));
+    }
+
+    @Test
+    public void testOptionalEnhancements() {
+        Optional<String> optional = Optional.empty();
+        Assertions.assertThrows(IllegalStateException.class, () -> optional.orElseThrow(IllegalStateException::new));
+        Assertions.assertEquals("", optional.stream().collect(Collectors.joining()));
+    }
+
+}