Added a negative test and a must constraint for at least one endpoint…

… (fix for issue #1)

.gitignore

@@ -15,4 +15,6 @@ pulls.json
 report.xml
 lib
 *.withyang
+*.yangdeps
+tmp-negative.out
 modules/

ietf-taps-api.yang

@@ -232,6 +232,9 @@ module ietf-taps-api {
   }
 
   container preconnection {
+    must "count(//preconnection/local-endpoints) > 0 or
+      count(//preconnection/remote-endpoints) > 0";
+
     description "preconnection config for a taps connection";
 
     list local-endpoints {

negative-ietf-taps-api-no-endpoints.expect

@@ -0,0 +1,3 @@
++ yanglint -f json -t data -D -s -V -p modules -p . ietf-taps-api.yang negative-ietf-taps-api-no-endpoints.json
+err : Must condition "count(//preconnection/local-endpoints) > 0 or
+count(//preconnection/remote-endpoints) > 0" not satisfied. (/ietf-taps-api:preconnection)

negative-ietf-taps-api-no-endpoints.json

@@ -0,0 +1,4 @@
+{
+  "ietf-taps-api:preconnection":{
+  }
+}

negative.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+input_yang=$1
+
+if [ ! -f "$input_yang" ] ; then
+  echo "no file $input_yang"
+  echo "usage: $0 <input>.yang :"
+  echo "  runs yanglint on all files named negative-<input>-*.json,"
+  echo "  with <input>.yang, and confirms that they all fail."
+  exit 1
+fi
+
+yangfile=$(basename -- "$input_yang")
+# extension="${yangfile##*.}"
+input="${yangfile%.*}"
+
+problems=0
+problems_in=""
+passed=""
+passed_count=0
+
+for f in $(ls negative-${input}-*.json); do
+  bash -x -e -c "yanglint -f json -t data -D -s -V -p modules -p . $input.yang $f" 2>&1 | grep -v "warn: Module's revisions are not unique (2018-06-28)" > tmp-negative.out
+
+  if [ "${PIPESTATUS[0]}" = "0" ]; then
+    problems=$((problems+1))
+    problems_in="$problems_in\\n  $f"
+  else
+    filename=$(basename -- "$f")
+    # extension="${filename##*.}"
+    basename="${filename%.*}"
+    if [ ! -e $basename.expect ]; then
+      echo "no such file: $basename.expect"
+      problems=$((problems+1))
+      problems_in="$problems_in\\n  $f"
+    else
+      if ! bash -x -c "diff $basename.expect tmp-negative.out"; then
+        problems=$((problems+1))
+        problems_in="$problems_in\\n  $f"
+      else
+        passed="$passed\\n  $f"
+        passed_count=$((passed_count+1))
+      fi
+    fi
+  fi
+done
+
+if [ "$problems" != "0" ]; then
+  printf "$problems negative tests had problems:"
+  printf "$problems_in\\n"
+  exit 1
+else
+  printf "all $passed_count negative tests passed:"
+  printf "$passed\\n"
+fi