Made the test for an invalid control type slightly more robust by not using either 0 or 5 for the fake object (but rather some other value that isn't the constant and that's also conveniently ASCII) and deduplicating the redundant tests.

common/controls.c

@@ -222,7 +222,8 @@ void *uiControlImplData(uiControl *c)
 }
 
 static uiControl testHookControlWithInvalidControlMarker = {
-	.controlID = 0,
+	// use something other than 0 here to make it look like accidental real data
+	.controlID = UINT32_C(0x5A5A5A5A),
 };
 
 uiControl *uiprivTestHookControlWithInvalidControlMarker(void)

test/controls.c

@@ -176,19 +176,7 @@ Test(CheckingNullControlIsProgrammerError)
 	endCheckProgrammerError(ctx);
 }
 
-// TODO should this test be the same as the following one instead?
 Test(CheckingNonControlIsProgrammerError)
-{
-	// TODO make sure this is fine; if not, just use the following check instead
-	static char buf[] = "this is not a uiControl but is big enough to at the very least not cause a problem with UB hopefully";
-	void *ctx;
-
-	ctx = beginCheckProgrammerError("uiCheckControlType(): object passed in not a uiControl");
-	uiCheckControlType(buf, uiControlType());
-	endCheckProgrammerError(ctx);
-}
-
-Test(CheckingControlWithoutControlMarkerIsProgrammerError)
 {
 	void *ctx;