Testing.md

+# Unit Testing Suite
+
+In order to assure that the preprocessor and building scripts work as intended, every script comes with a collection of tests.
+
+# Test Template
+
+Each test has 4 stages:
+* Prepare variables
+* Run the script to be tested (with different combinations of input arguments
+* Check the result, usually via a [`diff`](https://en.wikipedia.org/wiki/Diff) command.
+* Exit with exit code `1` if script is failed or continue with next test.
+
+Example taken from `test_preproc_wg.sh`:
+
+```bash
+#BEGIN Test 1: Preprocessor for Working Group
+T=1
+#echo "##################################################"
+echo "Test $T: Preprocessor for Working Group only .md file" 
+#echo "##################################################"
+
+# preparation
+RESEARCH_BUILD=$RESEARCH_TESTING/build
+rm -rf $RESEARCH_TESTING/build
+mkdir -p  $RESEARCH_BUILD
+REF_FILE=$RESEARCH_TESTING/aperiodSchr-preproc-wg.md
+cd $RESEARCH_TESTING
+
+# run script
+$RESEARCH_ROOT/bin/preproc_wg.sh aperiodSchr.md  >> $LOGFILE 2>&1
+
+#check results
+DIFF=$(diff $RESEARCH_TESTING/build/aperiodSchr.md $RESEARCH_TESTING/aperiodSchr-preproc-wg.md) 
+#echo "--------------------------------------------------"
+if [ "$DIFF" != "" ] && [ -f "$RESEARCH_BUILD/aperiodSchr.md" ]
+then
+    echo "Test $T: failed"
+    exit 1
+else
+    echo "Test $T: passed."
+fi
+#END Test 1
\ No newline at end of file