test and implementation for caching bower_components by default

bin/compile

@@ -8,6 +8,10 @@ set -o pipefail   # don't ignore exit codes when piping output
 set -o nounset    # fail on unset variables
 unset GIT_DIR     # Avoid GIT_DIR leak from previous build steps
 
+### Constants
+
+DEFAULT_CACHE="node_modules bower_components"
+
 ### Configure directories
 
 BUILD_DIR=${1:-}
@@ -94,8 +98,8 @@ restore_cache() {
   if [ "$cache_status" == "valid" ]; then
     local cache_directories=$(get_cache_directories)
     if [ "$cache_directories" == "" ]; then
-      echo "Loading 1 from cacheDirectories (default):"
-      restore_cache_directories "$BUILD_DIR" "$CACHE_DIR" "node_modules"
+      echo "Loading 2 from cacheDirectories (default):"
+      restore_cache_directories "$BUILD_DIR" "$CACHE_DIR" "$DEFAULT_CACHE"
     else
       echo "Loading $(echo $cache_directories | wc -w | xargs) from cacheDirectories (package.json):"
       restore_cache_directories "$BUILD_DIR" "$CACHE_DIR" $cache_directories
@@ -122,12 +126,12 @@ build_dependencies | indent
 
 cache_build() {
   local cache_directories=$(get_cache_directories)
-  
+
   echo "Clearing previous node cache"
   clear_cache
   if [ "$cache_directories" == "" ]; then
-    echo "Saving 1 cacheDirectories (default):"
-    save_cache_directories "$BUILD_DIR" "$CACHE_DIR" "node_modules"
+    echo "Saving 2 cacheDirectories (default):"
+    save_cache_directories "$BUILD_DIR" "$CACHE_DIR" "$DEFAULT_CACHE"
   else
     echo "Saving $(echo $cache_directories | wc -w | xargs) cacheDirectories (package.json):"
     save_cache_directories "$BUILD_DIR" "$CACHE_DIR" $cache_directories

test/run

 #!/usr/bin/env bash
 # See README.md for info on running these tests.
 
+testNodeModulesCached() {
+  cache=$(mktmpdir)
+
+  compile "caching" $cache
+  assertCaptured "Saving 2 cacheDirectories (default)"
+  assertCaptured "- node_modules"
+  assertCaptured "- bower_components (nothing to cache)"
+  assertEquals "1" "$(ls -1 $cache/node | grep node_modules | wc -l | tr -d ' ')"
+  assertCapturedSuccess
+}
+
 testBuildWithUserCacheDirectoriesCamel() {
   cache=$(mktmpdir)
 
@@ -300,16 +311,6 @@ testInvalidDependency() {
   assertCapturedError 1 ""
 }
 
-testNodeModulesCached() {
-  cache=$(mktmpdir)
-
-  compile "caching" $cache
-  assertCaptured "Saving 1 cacheDirectories (default)"
-  assertCaptured "- node_modules"
-  assertEquals "1" "$(ls -1 $cache/node | grep node_modules | wc -l | tr -d ' ')"
-  assertCapturedSuccess
-}
-
 testBuildWithUserCacheDirectories() {
   cache=$(mktmpdir)