Add JSON filter file and passing test

Author: Kevin Paulisse

lib/octocatalog-diff/catalog-diff/filter/json.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require_relative '../filter'
+
+require 'json'
+
+module OctocatalogDiff
+  module CatalogDiff
+    class Filter
+      # Filter based on equivalence of JSON objects for file resources with named extensions.
+      class JSON < OctocatalogDiff::CatalogDiff::Filter
+        # Public: Actually do the comparison of JSON objects for appropriate resources.
+        # Return true if the JSON objects are known to be equivalent. Return false if they
+        # are not equivalent, or if equivalence cannot be determined.
+        #
+        # @param diff_in [OctocatalogDiff::API::V1::Diff] Difference
+        # @param _options [Hash] Additional options (there are none for this filter)
+        # @return [Boolean] true if this difference is a JSON file with identical objects, false otherwise
+        def filtered?(diff, _options = {})
+          # Skip additions or removals - focus only on changes
+          return false unless diff.change?
+
+          # Make sure we are comparing file content for a file ending in .json extension
+          return false unless diff.type == 'File' && diff.structure == %w(parameters content)
+          return false unless diff.title =~ /\.json\z/i
+
+          # Attempt to convert the old value and new value into JSON objects. Assuming
+          # that doesn't error out, the return value is whether or not they're equal.
+          obj_old = ::JSON.parse(diff.old_value)
+          obj_new = ::JSON.parse(diff.new_value)
+          obj_old == obj_new
+        rescue # Rescue everything - if something failed, we aren't sure what's going on, so we'll return false.
+          false
+        end
+      end
+    end
+  end
+end

spec/octocatalog-diff/tests/catalog-diff/filter/json_spec.rb

@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require_relative '../../spec_helper'
+require OctocatalogDiff::Spec.require_path('/api/v1/diff')
+require OctocatalogDiff::Spec.require_path('/catalog-diff/filter/json')
+
+describe OctocatalogDiff::CatalogDiff::Filter::JSON do
+  let(:subject) { described_class.new }
+
+  describe '#filtered?' do
+    let(:str1a) { '{"foo":"bar"}' }
+    let(:str1b) { "{\n  \"foo\": \"bar\"\n}\n" }
+    let(:str2) { '{"foo":"baz"}' }
+
+    it 'should not filter out an added resource' do
+      diff = ['+', "File\ffoobar.json", { 'parameters' => { 'content' => str1a } }]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a removed resource' do
+      diff = ['-', "File\ffoobar.json", { 'parameters' => { 'content' => str1a } }]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a non-file resource' do
+      diff = ['~', "Exec\ffoobar.json\fparameters\fcontent", str1a, str1b]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a file whose extension is not .json' do
+      diff = ['~', "File\ffoobar.txt\fparameters\fcontent", str1a, str1b]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a change with no content change' do
+      diff = ['~', "File\ffoobar.json\fparameters\fowner", 'root', 'nobody']
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a change where JSON objects are dissimilar' do
+      diff = ['~', "File\ffoobar.json\fparameters\fcontent", str1a, str2]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a change where JSON is invalid' do
+      x_str = '---{ "blah": "foo" }'
+      diff = ['~', "File\ffoobar.json\fparameters\fcontent", x_str, x_str]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should not filter out a change where JSON is unparseable' do
+      x_str = "--- !ruby/object:This::Does::Not::Exist\n  foo: bar"
+      diff = ['~', "File\ffoobar.json\fparameters\fcontent", x_str, x_str]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(false)
+    end
+
+    it 'should filter out a whitespace-only change to a .json file' do
+      diff = ['~', "File\ffoobar.json\fparameters\fcontent", str1a, str1b]
+      diff_obj = OctocatalogDiff::API::V1::Diff.new(diff)
+      result = subject.filtered?(diff_obj)
+      expect(result).to eq(true)
+    end
+  end
+end