Add tests

lib/gitlab/diff/inline_diff.rb

@@ -38,6 +38,7 @@ module Gitlab
 
       private
 
+      # Find runs of single line edits
       def local_edit_indexes
         line_prefixes = @lines.map { |line| line.match(/\A([+-])/) ? $1 : ' ' }
         joined_line_prefixes = " #{line_prefixes.join} "

lib/gitlab/diff/inline_diff_marker.rb

@@ -11,9 +11,12 @@ module Gitlab
       def mark(line_inline_diffs)
         offset = 0
         line_inline_diffs.each do |inline_diff_range|
+          # Map the inline-diff range based on the raw line to character positions in the rich line
           inline_diff_positions = position_mapping[inline_diff_range]
+          # Turn the array of character positions into ranges
           marker_ranges = collapse_ranges(inline_diff_positions)
 
+          # Mark each range
           marker_ranges.each do |range|
             offset = insert_around_range(rich_line, range, "<span class='idiff'>", "</span>", offset)
           end
@@ -22,6 +25,9 @@ module Gitlab
         rich_line
       end
 
+      private
+
+      # Mapping of character positions in the raw line, to the rich (highlighted) line
       def position_mapping
         @position_mapping ||= begin
           mapping = []
@@ -31,6 +37,8 @@ module Gitlab
             raw_char = raw_line[raw_pos]
             rich_char = rich_line[rich_pos]
 
+            # The raw and rich lines are the same except for HTML tags,
+            # so skip over any `<...>` segment
             while rich_char == '<'
               until rich_char == '>'
                 rich_pos += 1
@@ -50,6 +58,7 @@ module Gitlab
         end
       end
 
+      # Takes an array of integers, and returns an array of ranges covering the same integers
       def collapse_ranges(positions)
         return [] if positions.empty?
         ranges = []
@@ -71,6 +80,7 @@ module Gitlab
         ranges
       end
 
+      # Inserts tags around the characters identified by the given range
       def insert_around_range(text, range, before, after, offset = 0)
         text.insert(offset + range.begin, before)
         offset += before.length

spec/lib/gitlab/diff/inline_diff_marker_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Diff::InlineDiffMarker, lib: true do
+  describe '#inline_diffs' do
+    let(:raw)  { "abc def" }
+    let(:rich) { %{<span class="abc">abc</span><span class="space"> </span><span class="def">def</span>} }
+    let(:inline_diffs) { [2..4] }
+
+    let(:subject) { Gitlab::Diff::InlineDiffMarker.new(raw, rich).mark(inline_diffs) }
+
+    it 'marks the inline diffs' do
+      expect(subject).to eq(%{<span class="abc">ab<span class='idiff'>c</span></span><span class="space"><span class='idiff'> </span></span><span class="def"><span class='idiff'>d</span>ef</span>})
+    end
+  end
+end

spec/lib/gitlab/diff/inline_diff_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Diff::InlineDiff, lib: true do
+  describe '#inline_diffs' do
+    let(:diff) do
+      <<eos
+ class Test
+-  def initialize(test = true)
++  def initialize(test = false)
+     @test = test
+   end
+ end
+eos
+    end
+
+    let(:subject) { Gitlab::Diff::InlineDiff.new(diff.lines).inline_diffs }
+
+    it 'finds all inline diffs' do
+      expect(subject[0]).to be_nil
+      expect(subject[1]).to eq([25..27])
+      expect(subject[2]).to eq([25..28])
+      expect(subject[3]).to be_nil
+      expect(subject[4]).to be_nil
+      expect(subject[5]).to be_nil
+    end
+  end
+end