test: Add test case for fpurge(NULL)
diff --git a/test/fpurge.c b/test/fpurge.c
index 8f2e996..03f107f 100644
--- a/test/fpurge.c
+++ b/test/fpurge.c
@@ -32,6 +32,9 @@ main()
static FILE fp_bad;
FILE *fp;
+ if (fpurge(NULL) == 0)
+ return 1;
+
if (fpurge(&fp_bad) == 0)
return 1;