[RFC 6/6] lib/test_printf.c: add a few fmtcheck() test cases

[Rasmus Villemoes <linux@rasmusvillemoes.dk>]

It should be trivial to add more test cases, once we figure out the
exact rules for being compatible or not. Perhaps we'll have to extend
the struct test with a flags element if we add flags that affect the
return value.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 lib/test_printf.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 563f10e6876a..0c8490f3a9b3 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -483,6 +483,45 @@ test_pointer(void)
 	flags();
 }
 
+static void __init
+test_fmtcheck(void)
+{
+	struct test { const char *fmt; const char *tmpl; };
+	static const struct test compatible[] __initconst = {
+		{"", ""},
+		{"wlan%d", "%d"},
+		{"aa%llxbb", "cc%Lxdd%%"},
+	};
+	static const struct test incompatible[] __initconst = {
+		{"a %d b %lx", "%d %x"},
+		{"%llo", "%Lx"},
+	};
+	unsigned i;
+	const struct test *t;
+	const char *ret;
+
+	for (i = 0; i < ARRAY_SIZE(compatible); ++i) {
+		total_tests++;
+		t = &compatible[i];
+		ret = _fmtcheck(t->fmt, t->tmpl, FMTCHECK_SILENT);
+		if (ret != t->fmt) {
+			failed_tests++;
+			pr_warn("'%s' and '%s' deemed incompatible by fmtcheck()",
+				t->fmt, t->tmpl);
+		}
+	}
+	for (i = 0; i < ARRAY_SIZE(incompatible); ++i) {
+		total_tests++;
+		t = &incompatible[i];
+		ret = _fmtcheck(t->fmt, t->tmpl, FMTCHECK_SILENT);
+		if (ret != t->tmpl) {
+			failed_tests++;
+			pr_warn("'%s' and '%s' deemed compatible by fmtcheck()",
+				t->fmt, t->tmpl);
+		}
+	}
+}
+
 static int __init
 test_printf_init(void)
 {
@@ -496,6 +535,8 @@ test_printf_init(void)
 	test_string();
 	test_pointer();
 
+	test_fmtcheck();
+
 	kfree(alloced_buffer);
 
 	if (failed_tests == 0)
-- 
2.11.0