revert change, test proper behavior

spec/configs/plugin_config_spec.cr

@@ -22,7 +22,7 @@ module Biplane
       plugin.member_route.to_s.should eq "/apis/#{parent.name}/plugins/:id"
     end
 
-    it "ignores empty values" do
+    it "passes through empty values" do
       yaml = <<-YAML
         name: 'datadog'
         attributes:
@@ -44,8 +44,8 @@ module Biplane
       empty_plugin = PluginConfig.from_yaml(yaml)
       config = empty_plugin.attributes["config"] as Hash
 
-      config.keys.should_not contain("tags")
-      # config["tags"].should eq Hash(String, PluginConfig::Type).new
+      config.keys.should contain("tags")
+      config["tags"].should eq Hash(String, PluginConfig::Type).new
     end
 
     it "can present config as params" do

spec/fixtures/datadog.json

@@ -0,0 +1,31 @@
+{
+  "api_id": "abc-123-583-123",
+  "config": {
+    "host": "datadog",
+    "timeout": 10000,
+    "metrics": [
+      "request_count",
+      "latency",
+      "request_size",
+      "status_count",
+      "response_size",
+      "unique_users",
+      "request_per_user"
+    ],
+    "port": 1234,
+    "tags": {
+      "latency": {},
+      "request_count": {},
+      "request_per_user": {},
+      "request_size": {},
+      "response_size": {},
+      "status_count": {},
+      "unique_users": {},
+      "upstream_latency": {}
+    }
+  },
+  "created_at": 1493065738000,
+  "enabled": true,
+  "id": "abc-123-456-123as",
+  "name": "datadog"
+}

spec/fixtures/datadog.yaml

@@ -0,0 +1,14 @@
+name: 'datadog'
+attributes:
+  config:
+    host: datadog
+    timeout: 10000
+    metrics:
+      - request_count
+      - latency
+      - request_size
+      - status_count
+      - response_size
+      - unique_users
+      - request_per_user
+    port: 1234

spec/mixins/normalize_attributes_spec.cr

@@ -35,10 +35,5 @@ module Biplane
       result = Dummy.new({"one": {"two": "three"}}).norm({"four": "five"})
       result.should eq({"one": {"two": "three"}, "four": "five"})
     end
-
-    it "ignores empty nests" do
-      result = Dummy.new({"one": {"two": "three"}}).norm({"four": Hash(String, String).new})
-      result.should eq({"one": {"two": "three"}})
-    end
   end
 end

spec/models/plugin_spec.cr

@@ -94,6 +94,13 @@ module Biplane
 
         plugin.diff(new_cfg).should eq({"attributes": {"config": Diff.new(nil, plugin.attributes["config"])}})
       end
+
+      it "will ignore nested empties" do
+        plugin = build_json_fixture(Plugin, "datadog")
+        cfg = build_yaml_fixture(PluginConfig, "datadog")
+
+        plugin.should eq(cfg)
+      end
     end
   end
 end

spec/spec_helper.cr

@@ -3,14 +3,22 @@ require "mock"
 
 require "../src/biplane"
 
+def build_json_fixture(type, name)
+  type.from_json File.read("./spec/fixtures/#{name}.json")
+end
+
+def build_yaml_fixture(type, name)
+  type.from_yaml File.read("./spec/fixtures/#{name}.yaml")
+end
+
 def json_fixture(type)
   base = type.name.split("::").last.downcase
-  type.from_json File.read("./spec/fixtures/#{base}.json")
+  build_json_fixture(type, base)
 end
 
 def yaml_fixture(type)
   base = type.name.split("::").last.gsub("Config", "").downcase
-  type.from_yaml File.read("./spec/fixtures/#{base}.yaml")
+  build_yaml_fixture(type, base)
 end
 
 def build_response(body : Hash | Nil, status = 200)

src/biplane/child_collection.cr

@@ -8,15 +8,15 @@ module Biplane
     delegate empty?, last, @collection
 
     def initialize(@collection : Array(T), @parent = nil)
-      @collection.map! {|item| item.parent = @parent; item } unless @parent.nil?
+      @collection.map! { |item| item.parent = @parent; item } unless @parent.nil?
     end
 
     def id_key
       T.child_key
     end
 
     def each
-      @collection.each {|item| yield item }
+      @collection.each { |item| yield item }
     end
 
     def lookup(id)
@@ -42,19 +42,21 @@ module Biplane
     end
 
     def diff(other : ChildCollection)
+      # if union of keys is empty, we have no comparable items
       all_keys = keys | other.keys
       return if all_keys.empty?
 
+      # compare on a key-by-key basis
       diffs = all_keys.map do |k|
         this_inst = lookup(k)
         other_inst = other.lookup(k)
 
         result = compare(this_inst, other_inst)
 
-        { k => result } if result && !result.empty?
+        {k => result} if result && !result.empty?
       end.compact
 
-      diffs.empty? ? nil : diffs.reduce {|memo, item| memo.merge(item) }
+      diffs.empty? ? nil : diffs.reduce { |memo, item| memo.merge(item) }
     end
 
     # Removal

src/biplane/config.cr

@@ -36,6 +36,7 @@ module Biplane
       io << serialize.to_s
     end
 
+    # overrides to allow for empty values
     private def valid_value?(value)
       !value.is_a?(Nil)
     end

src/biplane/mixins/normalize_attributes.cr

@@ -11,8 +11,6 @@ module Biplane::Mixins
     end
 
     private def normalize(memo, key, value)
-      return memo if value.is_a?(Hash) && value.empty?
-
       stretch_key(memo, key.split('.'), value)
     end