Add a few keyboard tests; fix missing input validation in SDL_GetKeyFromName

src/events/SDL_keyboard.c

@@ -953,6 +953,9 @@ SDL_GetKeyFromName(const char *name)
 {
 	SDL_Keycode key;
 
+        /* Check input */
+        if (name == NULL) return SDLK_UNKNOWN;
+        
 	/* If it's a single UTF-8 character, then that's the keycode itself */
 	key = *(const unsigned char *)name;
 	if (key >= 0xF0) {