diff --git a/README.md b/README.md
index e3c6248..f9557d3 100644
--- a/README.md
+++ b/README.md
@@ -8,9 +8,14 @@ Checks a given folder for certain file extensions recursively. All found files w
 
 The [check_folder_for_extension test folder](cffe_test) contains of 13 files, 12 of them images, which should be found by the test.
 
-function call:
+Function call:
 ```
-check_folder ./cffe_test "*.jpg *.JPG"
+check_folder $my_folder $extension_list
+```
+
+To test the function call:
+```
+check_folder_for_extension.sh ./cffe_test "*.jpg *.JPG"
 ```
 For multiple extensions (or other parts of the file name to match) space separate the list, like shown above.
 
@@ -59,3 +64,8 @@ produces the following message in the log file:
 ```
 logger 20231122_22:43:19 Warning: This is my message!
 ```
+
+For testing the function call the script with just:
+```
+logger.sh
+```
diff --git a/logger.sh b/logger.sh
index 130ff1c..2d0b928 100755
--- a/logger.sh
+++ b/logger.sh
@@ -6,10 +6,10 @@ LLWarning=3
 LLInfo=4
 LLDebug=5
 ## Actual log level of the logger used
-Log_Level=$LLDebug
+Log_Level=$LLInfo
 
-## Name of the logging script
-Log_Name="myscript";
+## base name of the logging script.
+Log_Name="${0##*/}";
 
 ## Write log of the script.
 ## $1 Loglevel to log the message with.
@@ -34,18 +34,79 @@ function logger() {
 	fi
 	printf "$Log_Name ${_now}${_type} ${_log_message}\n" >> $Log_File;
 	if [[ $Log_Level -eq $LLDebug ]]; then
-		printf "$Log_Name ${_now}${_type} ${_log_message}\n";
+		printf "${_now}${_type} ${_log_message}\n";
 	fi
 }
 
 function test() {
-	echo $DATE
+	printf "Running tests for logger().\n";
+	local _exit_val=0;
+	# Test log level mute: no logfile should be created!
+	Log_Level=$LLMute;
+	logger $LLMdtry "In level mute nothing should be logged!";
+	if [ -e "$Log_File" ]; then  # the logfile should not exist!
+		((_exit_val+=1))
+		printf "logger() test on log level Mute: FAILED!\n";
+		rm $Log_File;
+	else
+		printf "logger() test on log level Mute: OK.\n";
+	fi
+
+	# Test log level Mdtry, but log with level error: still no logfile should be created!
+	Log_Level=$LLMdtry;
+	logger $LLError "In level Mdtry an error should not be logged!";
+	if [ -e "$Log_File" ]; then  # the logfile should not exist!
+		((_exit_val+=1))
+		printf "logger() test on log level Mandatory; logging an error happend, so test FAILED!\n";
+		rm $Log_File;
+	else
+		printf "logger() test on log level Mandatory: when logging an error failed: test OK.\n";
+	fi
+
+	# Test log level Info, but log with level error: logfile should be created!
+	Log_Level=$LLInfo;
+	logger $LLError "In level Info an error should be logged!";
+	if [ -e "$Log_File" ]; then  # the logfile should now exist.
+		printf "logger() test on log level Info: logging an error succeeded, test OK.\n";
+		rm $Log_File;
+	else
+		((_exit_val+=1))
+		printf "logger() test on log level Info: logging an error FAILED!\n";
+	fi
+
+	# Test log level Info, but log with level debug: logfile should not be created!
+	Log_Level=$LLInfo;
+	logger $LLDebug "In level Info a debug message should not be logged!";
+	if [ -e "$Log_File" ]; then  # the logfile should not exist.
+		((_exit_val+=1))
+		printf "logger() test on log level Info: logging a debug message succeeded, so test FAILED!\n";
+		rm $Log_File;
+	else
+		printf "logger() test on log level Info: logging a debug message failed: test OK.\n";
+	fi
+
+	# Test log level Debug, but log with level debug: logfile should be created!
+	Log_Level=$LLDebug;
+	logger $LLDebug "In level Debug a debug message should be logged. ALso the message should appaer on std out.";
+	if [ -e "$Log_File" ]; then  # the logfile should not exist.
+		printf "logger() test on log level Debug: logging a debug message succeeded, so test OK.\n";
+		rm $Log_File;
+	else
+		((_exit_val+=1))
+		printf "logger() test on log level Debug: logging a debug message failed: test FAILED!\n";
+	fi
+
+	return $_exit_val;
 }
 
 DATE=$(which date);
 
 Run_Date=$($DATE +%Y_%m_%d)
-Log_File="/tmp/${Run_Date}_${Log_Name}.log";
-
+Log_File="${Run_Date}_${Log_Name}.log";
 
 test
+if [ $? -eq 0 ]; then
+	printf "All test succeeded.\n";
+else
+	printf "$? of 5 tests FAILED!\n";
+fi