Clean up TestCommand paraphenalia

spring-boot-cli/samples/test.groovy

@@ -0,0 +1,7 @@
+class BookTests {
+    @Test
+    void testBooks() {
+        Book book = new Book(author: "Tom Clancy", title: "Threat Vector")
+        assertEquals("Tom Clancy", book.author)
+    }
+}