diff --git a/tests/sys/progress_bar/Makefile b/tests/sys/progress_bar/Makefile
index 842ee1ee9452..1519c5ea504c 100644
--- a/tests/sys/progress_bar/Makefile
+++ b/tests/sys/progress_bar/Makefile
@@ -3,24 +3,10 @@ include ../Makefile.sys_common
 USEMODULE += xtimer
 USEMODULE += progress_bar
 
-CONFIG_PROGRESS_BAR_LENGTH ?= 50
-CONFIG_PROGRESS_BAR_FULL_CHARACTER ?= "█"
-CONFIG_PROGRESS_BAR_EMPTY_CHARACTER ?= " "
-
-# Other nice progress bar characters:
-#CONFIG_PROGRESS_BAR_FULL_CHARACTER ?= "◉"
-#CONFIG_PROGRESS_BAR_EMPTY_CHARACTER ?= "◯"
-#CONFIG_PROGRESS_BAR_FULL_CHARACTER ?= "▣"
-#CONFIG_PROGRESS_BAR_EMPTY_CHARACTER ?= "▢"
-
-CFLAGS += -DCONFIG_PROGRESS_BAR_FULL_CHARACTER=\"$(CONFIG_PROGRESS_BAR_FULL_CHARACTER)\"
-CFLAGS += -DCONFIG_PROGRESS_BAR_EMPTY_CHARACTER=\"$(CONFIG_PROGRESS_BAR_EMPTY_CHARACTER)\"
-CFLAGS += -DCONFIG_PROGRESS_BAR_LENGTH=$(CONFIG_PROGRESS_BAR_LENGTH)
-
 include $(RIOTBASE)/Makefile.include
 
-# Make custom progress bar characters available in Python test script via
-# environment variables
+# Make custom progress bar configuration from app.config
+# available in Python test script via environment variables
 export CONFIG_PROGRESS_BAR_FULL_CHARACTER
 export CONFIG_PROGRESS_BAR_EMPTY_CHARACTER
 export CONFIG_PROGRESS_BAR_LENGTH
diff --git a/tests/sys/progress_bar/app.config b/tests/sys/progress_bar/app.config
new file mode 100644
index 000000000000..312540e792e7
--- /dev/null
+++ b/tests/sys/progress_bar/app.config
@@ -0,0 +1,9 @@
+CONFIG_PROGRESS_BAR_LENGTH=50
+CONFIG_PROGRESS_BAR_FULL_CHARACTER="█"
+CONFIG_PROGRESS_BAR_EMPTY_CHARACTER=" "
+
+# Other nice progress bar characters:
+#CONFIG_PROGRESS_BAR_FULL_CHARACTER="◉"
+#CONFIG_PROGRESS_BAR_EMPTY_CHARACTER="◯"
+#CONFIG_PROGRESS_BAR_FULL_CHARACTER="▣"
+#CONFIG_PROGRESS_BAR_EMPTY_CHARACTER="▢"
diff --git a/tests/sys/progress_bar/tests/01-run.py b/tests/sys/progress_bar/tests/01-run.py
index f7b4ed1b1dfc..e9c1a8192b61 100755
--- a/tests/sys/progress_bar/tests/01-run.py
+++ b/tests/sys/progress_bar/tests/01-run.py
@@ -18,14 +18,14 @@
 
 
 def testfunc(child):
-    for i in range(0, 100, 10):
+    for i in range(0, 101, 10):
         ratio = int(i * LENGTH / 100.0)
         progress_str = FULL_CHARACTER * ratio
         progress_str += EMPTY_CHARACTER * (LENGTH - ratio)
         check_str = 'Progress bar 0 |{}| {:3}%'.format(
             progress_str, i)
         # todo: temporary printout for debugging this flaky test
-        print("EXPECTS:", check_str)
+        print("EXPECTS:", check_str, "LENGTH:", LENGTH, "ratio:", ratio)
         child.expect_exact(check_str)
     child.expect_exact("Done!")