test: add test for creating a VM with null config and fix wrenNewVM to handle NULL config

test/api/main.c

@@ -9,6 +9,7 @@
 #include "get_variable.h"
 #include "foreign_class.h"
 #include "lists.h"
+#include "new_vm.h"
 #include "slots.h"
 #include "value.h"
 
@@ -44,6 +45,9 @@ static WrenForeignMethodFn bindForeignMethod(
   method = listsBindMethod(fullName);
   if (method != NULL) return method;
   
+  method = newVMBindMethod(fullName);
+  if (method != NULL) return method;
+  
   method = slotsBindMethod(fullName);
   if (method != NULL) return method;
   

test/api/new_vm.c

@@ -0,0 +1,21 @@
+#include <string.h>
+
+#include "new_vm.h"
+
+static void nullConfig(WrenVM* vm)
+{
+  WrenVM* otherVM = wrenNewVM(NULL);
+  
+  // We should be able to execute code.
+  WrenInterpretResult result = wrenInterpret(otherVM, "1 + 2");
+  wrenSetSlotBool(vm, 0, result == WREN_RESULT_SUCCESS);
+  
+  wrenFreeVM(otherVM);
+}
+
+WrenForeignMethodFn newVMBindMethod(const char* signature)
+{
+  if (strcmp(signature, "static VM.nullConfig()") == 0) return nullConfig;
+
+  return NULL;
+}

test/api/new_vm.h

@@ -0,0 +1,3 @@
+#include "wren.h"
+
+WrenForeignMethodFn newVMBindMethod(const char* signature);

test/api/new_vm.wren

@@ -0,0 +1,6 @@
+class VM {
+  foreign static nullConfig()
+}
+// TODO: Other configuration settings.
+
+System.print(VM.nullConfig()) // expect: true