diff --git a/test/controls_windows.c b/test/controls_windows.c
new file mode 100644
index 00000000..04302205
--- /dev/null
+++ b/test/controls_windows.c
@@ -0,0 +1,25 @@
+// 10 june 2019
+#include "test_windows.h"
+
+static const uiControlOSVtable osVtable = {
+	.Size = sizeof (uiControlOSVtable),
+};
+
+const uiControlOSVtable *testOSVtable(void)
+{
+	return &osVtable;
+}
+
+Test(WrongControlOSVtableSizeIsProgrammerError)
+{
+	uiControlVtable vtable;
+	uiControlOSVtable osvt;
+	void *ctx;
+
+	testControlLoadNopVtable(&vtable);
+	ctx = beginCheckProgrammerError("uiRegisterControlType(): wrong size 1 for uiControlOSVtable");
+	memset(&osvt, 0, sizeof (uiControlOSVtable));
+	osvt.Size = 1;
+	uiRegisterControlType("name", &vtable, &osvt, 0);
+	endCheckProgrammerError(ctx);
+}
diff --git a/test/meson.build b/test/meson.build
index 28d87f94..2cee2e93 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -9,7 +9,11 @@ libui_test_sources = files([
 libui_allcalls_headers = files([
 	'allcalls.h',
 ])
-if libui_OS == 'darwin'
+if libui_OS == 'windows'
+	libui_test_sources += files([
+		'controls_windows.c',
+	])
+elif libui_OS == 'darwin'
 	libui_test_sources += files([
 		'controls_darwin.m',
 	])
diff --git a/zNEW_test/test_windows.h b/test/test_windows.h
similarity index 100%
rename from zNEW_test/test_windows.h
rename to test/test_windows.h
diff --git a/zNEW_test/controls_windows.c b/zNEW_test/controls_windows.c
deleted file mode 100644
index affdb52b..00000000
--- a/zNEW_test/controls_windows.c
+++ /dev/null
@@ -1,11 +0,0 @@
-// 10 june 2019
-#include "test_windows.h"
-
-static const uiControlOSVtable vtable = {
-	.Size = sizeof (uiControlOSVtable),
-};
-
-const uiControlOSVtable *testOSVtable(void)
-{
-	return &vtable;
-}
diff --git a/zNEW_test/controls_windows_errors.cpp b/zNEW_test/controls_windows_errors.cpp
deleted file mode 100644
index 56b7c3e2..00000000
--- a/zNEW_test/controls_windows_errors.cpp
+++ /dev/null
@@ -1,17 +0,0 @@
-// 16 june 2019
-#include "test_windows.h"
-
-const struct checkErrorCase controlOSVtableCases[] = {
-	{
-		"uiRegisterControlType() with OS vtable with wrong size",
-		[](void) {
-			uiControlOSVtable vtable;
-		
-			memset(&vtable, 0, sizeof (uiControlOSVtable));
-			vtable.Size = 1;
-			uiRegisterControlType("name", testVtable(), &vtable, 0);
-		},
-		"uiRegisterControlType(): wrong size 1 for uiControlOSVtable",
-	},
-	{ NULL, NULL, NULL },
-};