Add NoDuplicateTags check

Author: mpchadwick

lib/jekyll-pre-commit.rb

@@ -10,3 +10,4 @@ module PreCommit
 require 'jekyll-pre-commit/checks/front_matter_variable_exists.rb'
 require 'jekyll-pre-commit/checks/front_matter_variable_is_not_duplicate.rb'
 require 'jekyll-pre-commit/checks/front_matter_variable_meets_length_requirements.rb'
+require 'jekyll-pre-commit/checks/no_duplicate_tags.rb'

lib/jekyll-pre-commit/checks/no_duplicate_tags.rb

@@ -0,0 +1,41 @@
+module Jekyll
+  module PreCommit
+    module Checks
+      class NoDuplicateTags < Check
+        def check(staged, not_staged, site, args)
+          raw = Hash.new
+          normalized = Hash.new
+          not_staged.each do |post|
+            if post.data["tags"].size > 0
+              post.data["tags"].each do |tag|
+                if !raw[tag]
+                  raw[tag] = post.relative_path
+                end
+
+                n = Jekyll::Utils.slugify(tag)
+                if !normalized[n]
+                  normalized[n] = post.relative_path
+                end
+              end
+            end
+          end
+
+          staged.each do |post|
+            if post.data["tags"].size > 0
+              post.data["tags"].each do |tag|
+                n = Jekyll::Utils.slugify(tag)
+
+                if normalized[n] && !raw[tag]
+                  @result[:ok] = false
+                  @result[:message] += "#{tag} appears to be duplicated in #{normalized[n]}!"
+                end
+              end
+            end
+          end
+
+          @result
+        end
+      end
+    end
+  end
+end

spec/fixtures/_posts/2017-07-24-duplicate-tags-1.md

@@ -0,0 +1,9 @@
+---
+layout: post
+title:  "Duplicate Tags 1"
+description: Duplicate Tags 1
+image: Duplicate Tags 1
+tags: ["Duplicate"]
+---
+
+!

spec/fixtures/_posts/2017-07-24-duplicate-tags-2.md

@@ -0,0 +1,9 @@
+---
+layout: post
+title:  "Duplicate Tags 2"
+description: Duplicate Tags 2
+image: Duplicate Tags 2
+tags: ["duplicate"]
+---
+
+!

spec/fixtures/_posts/2017-07-24-has-unique-tags.md

@@ -0,0 +1,9 @@
+---
+layout: post
+title:  "Unique Tags"
+description: Unique Tags
+image: Unique Tags
+tags: ["unique"]
+---
+
+!

spec/jekyll-pre-commit_spec.rb

@@ -182,6 +182,29 @@
     end
   end
 
+  context "with NoDuplicateTags" do
+    pre_commit_config = {"check" => "NoDuplicateTags"}
+    let(:site) { build_site({ 'pre-commit' => [pre_commit_config] }) }
+
+    it "passes if a staged post has no tags" do
+      result = runner.run(site, ["spec/fixtures/_posts/2017-01-06-description-is-too-long.md"])
+      expect(result[:ok]).to eql(true)
+      expect(result[:messages]).to match_array([])
+    end
+
+    it "passes if a staged post has tags, but no duplicated" do
+      result = runner.run(site, ["spec/fixtures/_posts/2017-07-24-has-unique-tags.md"])
+      expect(result[:ok]).to eql(true)
+      expect(result[:messages]).to match_array([])
+    end
+
+    it "fails if a staged post has duplicate tags" do
+      result = runner.run(site, ["spec/fixtures/_posts/2017-07-24-duplicate-tags-2.md"])
+      expect(result[:ok]).to eql(false)
+      expect(result[:messages]).to match_array(["duplicate appears to be duplicated in _posts/2017-07-24-duplicate-tags-1.md!"])
+    end
+  end
+
   context "with a check that doesn't exist" do
     pre_commit_config = {"check" => "Garbage"}
     let(:site) { build_site({ 'pre-commit' => [pre_commit_config] }) }