diff --git a/test/controls_errors.cpp b/test/controls_errors.cpp
index 9dfdd4cd..27dd1ab9 100644
--- a/test/controls_errors.cpp
+++ b/test/controls_errors.cpp
@@ -1,7 +1,7 @@
 // 11 june 2019
 #include "test.h"
 
-static const struct checkErrorCase cases[] = {
+static const struct checkErrorCase casesBeforeOSVtable[] = {
 	{
 		"uiRegisterControlType() with NULL name",
 		[](void) {
@@ -47,11 +47,79 @@ static const struct checkErrorCase cases[] = {
 		},
 		"uiRegisterControlType(): invalid null pointer for uiControlOSVtable",
 	},
-	// OS vtable sizes are tested per-OS
+	{ NULL, NULL, NULL },
+};
+
+static const struct checkErrorCase casesAfterOSVtable[] = {
+	{
+		"uiCheckControlType() with a NULL pointer",
+		[](void) {
+			uiCheckControlType(NULL, uiControlType());
+		},
+		"TODO",
+	},
+	{
+		"uiCheckControlType() with non-control",
+		[](void) {
+			static char buf[] = "this is not a uiControl";
+
+			uiCheckControlType(buf, uiControlType());
+		},
+		"TODO",
+	},
+	{
+		"uiCheckControlType() with a control with an unknown type",
+		[](void) {
+			// TODO
+		},
+		"TODO",
+	},
+	{
+		"uiCheckControlType() asking for an unknown control type",
+		[](void) {
+			// TODO
+		},
+		"TODO",
+	},
+	{
+		"uiCheckControlType() with a type mismatch",
+		[](void) {
+			// TODO
+		},
+		"TODO",
+	},
+
+	{
+		"uiNewControl() with uiControlType()",
+		[](void) {
+			uiNewControl(uiControlType(), NULL);
+		},
+		"TODO",
+	},
+	{
+		"uiNewControl() with an unknown control type",
+		[](void) {
+			uiNewControl(5, NULL);
+		},
+		"TODO",
+	},
+	// TODO have Init() fail
+
+	// TODO uiControlFree()
+
+	{
+		"uiControlImplData() with a NULL uiControl",
+		[](void) {
+			uiControlImplData(NULL);
+		},
+		"TODO",
+	},
 	{ NULL, NULL, NULL },
 };
 
 testingTest(ControlErrors)
 {
-	checkProgrammerErrors(t, cases);
+	checkProgrammerErrors(t, casesBeforeOSVtable);
+	// OS vtable sizes are tested per-OS
+	checkProgrammerErrors(t, casesAfterOSVtable);
 }