test: net: lib: prometheus: formatter: Fix test flakiness

rlubos · dkalowsk · commit a597feafb8e5 · 2024-11-06T09:53:29.000-08:00
If a string is already present in the provided buffer,
prometheus_format_exposition() appends it instead of overwriting,
hence the buffer needs to be cleared on the test start, otherwise it
works by chance.

Signed-off-by: Robert Lubos &lt;robert.lubos@nordicsemi.no&gt;
diff --git a/tests/net/lib/prometheus/formatter/src/main.c b/tests/net/lib/prometheus/formatter/src/main.c
@@ -36,7 +36,7 @@ PROMETHEUS_COLLECTOR_DEFINE(test_custom_collector);
 ZTEST(test_formatter, test_prometheus_formatter_simple)
 {
 	int ret;
-	char formatted[MAX_BUFFER_SIZE];
+	char formatted[MAX_BUFFER_SIZE] = { 0 };
 	struct prometheus_counter *counter;
 	char exposed[] = "# HELP test_counter Test counter\n"
 			 "# TYPE test_counter counter\n"

Original file line number	Diff line number	Diff line change
`@@ -36,7 +36,7 @@ PROMETHEUS_COLLECTOR_DEFINE(test_custom_collector);`
`36`	`36`	`ZTEST(test_formatter, test_prometheus_formatter_simple)`
`37`	`37`	`{`
`38`	`38`	`int ret;`
`39`		`- char formatted[MAX_BUFFER_SIZE];`
	`39`	`+ char formatted[MAX_BUFFER_SIZE] = { 0 };`
`40`	`40`	`struct prometheus_counter *counter;`
`41`	`41`	`char exposed[] = "# HELP test_counter Test counter\n"`
`42`	`42`	`"# TYPE test_counter counter\n"`