diff --git a/test/controls.c b/test/controls.c
index 4e6d98ed..62458f7c 100644
--- a/test/controls.c
+++ b/test/controls.c
@@ -7,9 +7,12 @@ struct testImplData {
 	bool testMethodCalled;
 };
 
+static int failInit = 5;
+void *testControlFailInit = &failInit;
+
 static bool testVtableInit(uiControl *c, void *implData, void *initData)
 {
-	return true;
+	return initData != testControlFailInit;
 }
 
 static void testVtableFree(uiControl *c, void *implData)
@@ -35,3 +38,4 @@ size_t testImplDataSize(void)
 
 // TODO explicitly make/document 0 as always invalid
 uint32_t testControlType = 0;
+uint32_t testControlType2 = 0;
diff --git a/test/controls_errors.cpp b/test/controls_errors.cpp
index fe9c9011..f581e32f 100644
--- a/test/controls_errors.cpp
+++ b/test/controls_errors.cpp
@@ -80,16 +80,24 @@ static const struct checkErrorCase casesAfterOSVtable[] = {
 	{
 		"uiCheckControlType() asking for an unknown control type",
 		[](void) {
-			// TODO
+			uiControl *c;
+
+			c = uiNewControl(testControlType, NULL);
+			uiCheckControlType(c, 5);
+			uiControlFree(c);
 		},
-		"TODO",
+		"uiCheckControlType(): unknown uiControl type 5 requested",
 	},
 	{
 		"uiCheckControlType() with a type mismatch",
 		[](void) {
-			// TODO
+			uiControl *c;
+
+			c = uiNewControl(testControlType, NULL);
+			uiCheckControlType(c, testControlType2);
+			uiControlFree(c);
 		},
-		"TODO",
+		"uiCheckControlType(): wrong uiControl type passed: got TestControl, want TestControl2",
 	},
 
 	{
@@ -106,9 +114,28 @@ static const struct checkErrorCase casesAfterOSVtable[] = {
 		},
 		"uiNewControl(): unknown uiControl type 5 requested",
 	},
-	// TODO have Init() fail
+	{
+		"uiNewControl() with Init() failing",
+		[](void) {
+			uiNewControl(testControlType, testControlFailInit);
+		},
+		"uiNewControl(): invalid init data for TestControl",
+	},
 
-	// TODO uiControlFree()
+	{
+		"uiControlFree() with a NULL uiControl",
+		[](void) {
+			uiControlFree(NULL);
+		},
+		"uiControlFree(): invalid null pointer for uiControl",
+	},
+	{
+		"uiControlFree() with a uiControl that still has a parent",
+		[](void) {
+			// TODO
+		},
+		"TODO",
+	},
 
 	{
 		"uiControlImplData() with a NULL uiControl",
diff --git a/test/main.c b/test/main.c
index bfbf9470..d335ff8c 100644
--- a/test/main.c
+++ b/test/main.c
@@ -50,6 +50,8 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 	testControlType = uiRegisterControlType("TestControl", testVtable(), testOSVtable(), testImplDataSize());
+	testControlType2 = uiRegisterControlType("TestControl2", testVtable(), testOSVtable(), testImplDataSize());
+
 	runSetORingResults(NULL, &opts, &anyRun, &anyFailed);
 
 	if (!anyRun)
diff --git a/test/test.h b/test/test.h
index 87ec0bb4..43426463 100644
--- a/test/test.h
+++ b/test/test.h
@@ -50,10 +50,12 @@ extern void checkProgrammerErrorsFull(testingT *t, const char *file, long line,
 #define checkProgrammerErrorsInThread(t, cases) checkProgrammerErrorsFull(t, __FILE__, __LINE__, cases, true)
 
 // controls.c
+extern void *testControlFailInit;
 extern const uiControlVtable *testVtable(void);
 extern const uiControlOSVtable *testOSVtable(void);
 extern size_t testImplDataSize(void);
 extern uint32_t testControlType;
+extern uint32_t testControlType2;
 
 #ifdef __cplusplus
 }