test and implementation for error on failure to parse package.json

bin/compile

@@ -31,26 +31,7 @@ trap build_failed ERR
 ####### Determine current state
 
 head "Reading application state"
-
-info "package.json..."
-iojs_engine=$(read_json "$build_dir/package.json" ".engines.iojs")
-node_engine=$(read_json "$build_dir/package.json" ".engines.node")
-npm_engine=$(read_json "$build_dir/package.json" ".engines.npm")
-
-info "build directory..."
-start_method=$(get_start_method "$build_dir")
-modules_source=$(get_modules_source "$build_dir")
-
-info "cache directory..."
-npm_previous=$(file_contents "$cache_dir/node/npm-version")
-node_previous=$(file_contents "$cache_dir/node/node-version")
-modules_cached=$(get_modules_cached "$cache_dir")
-
-info "environment variables..."
-export_env_dir $env_dir
-export NPM_CONFIG_PRODUCTION=${NPM_CONFIG_PRODUCTION:-true}
-export NODE_MODULES_CACHE=${NODE_MODULES_CACHE:-true}
-
+read_current_state
 show_current_state
 
 if [ "$iojs_engine" == "" ]; then

bin/test

@@ -24,7 +24,7 @@ testBadJson() {
   assertCaptured "We're sorry this build is failing"
   assertNotCaptured "build directory..."
   assertNotCaptured "Installing binaries"
-  assertCapturedError 1 ""
+  assertCapturedError 1 "Unable to parse"
 }
 
 testIoJs() {
@@ -206,6 +206,7 @@ testProcfileAbsentNpmStartPresent() {
 testProcfileAbsentNpmStartAbsent() {
   compile "procfile-absent-npm-start-absent"
   assertCaptured "Start mechanism:     none"
+  assertCaptured "None found"
   assertNotCaptured "new Procfile"
   assertCapturedSuccess
 }

lib/build.sh

@@ -53,6 +53,39 @@ get_modules_cached() {
   fi
 }
 
+# Sets:
+# iojs_engine
+# node_engine
+# npm_engine
+# start_method
+# modules_source
+# npm_previous
+# node_previous
+# modules_cached
+# environment variables (from ENV_DIR)
+
+read_current_state() {
+  info "package.json..."
+  assert_json "$build_dir/package.json"
+  iojs_engine=$(read_json "$build_dir/package.json" ".engines.iojs")
+  node_engine=$(read_json "$build_dir/package.json" ".engines.node")
+  npm_engine=$(read_json "$build_dir/package.json" ".engines.npm")
+
+  info "build directory..."
+  start_method=$(get_start_method "$build_dir")
+  modules_source=$(get_modules_source "$build_dir")
+
+  info "cache directory..."
+  npm_previous=$(file_contents "$cache_dir/node/npm-version")
+  node_previous=$(file_contents "$cache_dir/node/node-version")
+  modules_cached=$(get_modules_cached "$cache_dir")
+
+  info "environment variables..."
+  export_env_dir $env_dir
+  export NPM_CONFIG_PRODUCTION=${NPM_CONFIG_PRODUCTION:-true}
+  export NODE_MODULES_CACHE=${NODE_MODULES_CACHE:-true}
+}
+
 show_current_state() {
   echo ""
   if [ "$iojs_engine" == "" ]; then
@@ -172,6 +205,8 @@ ensure_procfile() {
   elif [ "$start_method" == "server.js" ]; then
     info "No Procfile; Adding 'web: node server.js' to new Procfile"
     echo "web: node server.js" > $build_dir/Procfile
+  else
+    info "None found"
   fi
 }
 

lib/common.sh

 error() {
   echo " !     $*" >&2
-  exit 1
+  echo ""
+  return 1
 }
 
 head() {
@@ -27,6 +28,15 @@ achievement() {
   echo ""
 }
 
+assert_json() {
+  local file=$1
+  if test -f $file; then
+    if ! cat $file | $bp_dir/vendor/jq '.' > /dev/null; then
+      error "Unable to parse $file as JSON"
+    fi
+  fi
+}
+
 file_contents() {
   if test -f $1; then
     echo "$(cat $1)"