From fc6dc25da42782f9804ecf7e7f55b31277af3dd2 Mon Sep 17 00:00:00 2001
From: Martine Lenders <m.lenders@fu-berlin.de>
Date: Mon, 12 Apr 2021 11:39:10 +0200
Subject: [PATCH] tests/periph_rtt_min: harden test

- Better self-containment: read number of expected samples from output
  rather than the environment
- Less reliance on `stdout` timing: Count samples in application and
  output it rather then counting flushed dots.
---
 tests/periph_rtt_min/Makefile        |  2 --
 tests/periph_rtt_min/main.c          |  5 ++++-
 tests/periph_rtt_min/tests/01-run.py | 13 +++++++------
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/tests/periph_rtt_min/Makefile b/tests/periph_rtt_min/Makefile
index 82af2f49db..894f3ac1ce 100644
--- a/tests/periph_rtt_min/Makefile
+++ b/tests/periph_rtt_min/Makefile
@@ -23,5 +23,3 @@ else
   SAMPLES ?= 1024
 endif
 CFLAGS += -DSAMPLES=$(SAMPLES)
-
-$(call target-export-variables, test, SAMPLES)
diff --git a/tests/periph_rtt_min/main.c b/tests/periph_rtt_min/main.c
index 369b61e203..6c86b26e7a 100644
--- a/tests/periph_rtt_min/main.c
+++ b/tests/periph_rtt_min/main.c
@@ -44,6 +44,7 @@ void cb(void *arg)
 int main(void)
 {
     uint32_t value = 0;
+    uint32_t samples = 0;
     /* mutex starts out locked, and each time an rtt callback is successfully
        called it will be locked again for the next iteration */
     mutex_t lock = MUTEX_INIT_LOCKED;
@@ -69,10 +70,12 @@ int main(void)
         }
         printf(".");
         fflush(stdout);
+        samples++;
     }
     printf("\n");
 
-    printf("RTT_MIN_OFFSET for %s: %" PRIu32 "\n", RIOT_BOARD, value);
+    printf("RTT_MIN_OFFSET for %s over %" PRIu32 " samples: %" PRIu32 "\n",
+           RIOT_BOARD, samples, value);
 
     return 0;
 }
diff --git a/tests/periph_rtt_min/tests/01-run.py b/tests/periph_rtt_min/tests/01-run.py
index 17ba5eaba5..1a9f27c490 100755
--- a/tests/periph_rtt_min/tests/01-run.py
+++ b/tests/periph_rtt_min/tests/01-run.py
@@ -6,18 +6,19 @@
 # General Public License v2.1. See the file LICENSE in the top level
 # directory for more details.
 
-import os
 import sys
 
 from testrunner import run
 
-SAMPLES = int(os.getenv("SAMPLES", "1024"))
-
 
 def testfunc(child):
-    for _ in range(0, SAMPLES):
-        child.expect_exact('.')
-    child.expect(r'RTT_MIN_OFFSET for [a-zA-Z\-\_0-9]+: \d+')
+    child.expect(r"Evaluate RTT_MIN_OFFSET over (\d+) samples")
+
+    exp_samples = int(child.match.group(1))
+    child.expect(
+        r'RTT_MIN_OFFSET for [a-zA-Z\-\_0-9]+ over {samples} samples: \d+'
+        .format(samples=exp_samples)
+    )
 
 
 if __name__ == "__main__":