Fixed test specs

- added suggestions to mock data
- fixed props to be not required

14 files changed, 572 insertions, 166 deletions

diff --git a/spec/controllers/projects_controller_spec.rb b/spec/controllers/projects_controller_spec.rb
index 356d606d5c5..56d38b9475e 100644
--- a/spec/controllers/projects_controller_spec.rb
+++ b/spec/controllers/projects_controller_spec.rb
@@ -703,6 +703,16 @@ describe ProjectsController do
       expect(JSON.parse(response.body).keys).to match_array(%w(body references))
     end
 
+    context 'when not authorized' do
+      let(:private_project) { create(:project, :private) }
+
+      it 'returns 404' do
+        post :preview_markdown, params: { namespace_id: private_project.namespace, id: private_project, text: '*Markdown* text' }
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
     context 'state filter on references' do
       let(:issue) { create(:issue, :closed, project: public_project) }
       let(:merge_request) { create(:merge_request, :closed, target_project: public_project) }
diff --git a/spec/features/merge_request/user_suggests_changes_on_diff_spec.rb b/spec/features/merge_request/user_suggests_changes_on_diff_spec.rb
index c19e299097e..1b5dd6945e0 100644
--- a/spec/features/merge_request/user_suggests_changes_on_diff_spec.rb
+++ b/spec/features/merge_request/user_suggests_changes_on_diff_spec.rb
@@ -6,6 +6,14 @@ describe 'User comments on a diff', :js do
   include MergeRequestDiffHelpers
   include RepoHelpers
 
+  def expect_suggestion_has_content(element, expected_changing_content, expected_suggested_content)
+    changing_content = element.all(:css, '.line_holder.old').map(&:text)
+    suggested_content = element.all(:css, '.line_holder.new').map(&:text)
+
+    expect(changing_content).to eq(expected_changing_content)
+    expect(suggested_content).to eq(expected_suggested_content)
+  end
+
   let(:project) { create(:project, :repository) }
   let(:merge_request) do
     create(:merge_request_with_diffs, source_project: project, target_project: project, source_branch: 'merge-test')
@@ -33,8 +41,18 @@ describe 'User comments on a diff', :js do
       page.within('.diff-discussions') do
         expect(page).to have_button('Apply suggestion')
         expect(page).to have_content('Suggested change')
-        expect(page).to have_content('	url = https://github.com/gitlabhq/gitlab-shell.git')
-        expect(page).to have_content('# change to a comment')
+      end
+
+      page.within('.md-suggestion-diff') do
+        expected_changing_content = [
+          "6 url = https://github.com/gitlabhq/gitlab-shell.git"
+        ]
+
+        expected_suggested_content = [
+          "6 # change to a comment"
+        ]
+
+        expect_suggestion_has_content(page, expected_changing_content, expected_suggested_content)
       end
     end
 
@@ -64,7 +82,7 @@ describe 'User comments on a diff', :js do
       click_diff_line(find("[id='#{sample_compare.changes[1][:line_code]}']"))
 
       page.within('.js-discussion-note-form') do
-        fill_in('note_note', with: "```suggestion\n# change to a comment\n```\n```suggestion\n# or that\n```")
+        fill_in('note_note', with: "```suggestion\n# change to a comment\n```\n```suggestion:-2\n# or that\n# heh\n```")
         click_button('Comment')
       end
 
@@ -74,11 +92,90 @@ describe 'User comments on a diff', :js do
         suggestion_1 = page.all(:css, '.md-suggestion-diff')[0]
         suggestion_2 = page.all(:css, '.md-suggestion-diff')[1]
 
-        expect(suggestion_1).to have_content('	url = https://github.com/gitlabhq/gitlab-shell.git')
-        expect(suggestion_1).to have_content('# change to a comment')
+        suggestion_1_expected_changing_content = [
+          "6 url = https://github.com/gitlabhq/gitlab-shell.git"
+        ]
+        suggestion_1_expected_suggested_content = [
+          "6 # change to a comment"
+        ]
+
+        suggestion_2_expected_changing_content = [
+          "4 [submodule \"gitlab-shell\"]",
+          "5 path = gitlab-shell",
+          "6 url = https://github.com/gitlabhq/gitlab-shell.git"
+        ]
+        suggestion_2_expected_suggested_content = [
+          "4 # or that",
+          "5 # heh"
+        ]
+
+        expect_suggestion_has_content(suggestion_1,
+                                      suggestion_1_expected_changing_content,
+                                      suggestion_1_expected_suggested_content)
+
+        expect_suggestion_has_content(suggestion_2,
+                                      suggestion_2_expected_changing_content,
+                                      suggestion_2_expected_suggested_content)
+      end
+    end
+  end
+
+  context 'multi-line suggestions' do
+    it 'suggestion is presented' do
+      click_diff_line(find("[id='#{sample_compare.changes[1][:line_code]}']"))
+
+      page.within('.js-discussion-note-form') do
+        fill_in('note_note', with: "```suggestion:-3+5\n# change to a\n# comment\n# with\n# broken\n# lines\n```")
+        click_button('Comment')
+      end
 
-        expect(suggestion_2).to have_content('	url = https://github.com/gitlabhq/gitlab-shell.git')
-        expect(suggestion_2).to have_content('# or that')
+      wait_for_requests
+
+      page.within('.diff-discussions') do
+        expect(page).to have_button('Apply suggestion')
+        expect(page).to have_content('Suggested change')
+      end
+
+      page.within('.md-suggestion-diff') do
+        expected_changing_content = [
+          "3 url = git://github.com/randx/six.git",
+          "4 [submodule \"gitlab-shell\"]",
+          "5 path = gitlab-shell",
+          "6 url = https://github.com/gitlabhq/gitlab-shell.git",
+          "7 [submodule \"gitlab-grack\"]",
+          "8 path = gitlab-grack",
+          "9 url = https://gitlab.com/gitlab-org/gitlab-grack.git"
+        ]
+
+        expected_suggested_content = [
+          "3 # change to a",
+          "4 # comment",
+          "5 # with",
+          "6 # broken",
+          "7 # lines"
+        ]
+
+        expect_suggestion_has_content(page, expected_changing_content, expected_suggested_content)
+      end
+    end
+
+    it 'suggestion is appliable' do
+      click_diff_line(find("[id='#{sample_compare.changes[1][:line_code]}']"))
+
+      page.within('.js-discussion-note-form') do
+        fill_in('note_note', with: "```suggestion:-3+5\n# change to a\n# comment\n# with\n# broken\n# lines\n```")
+        click_button('Comment')
+      end
+
+      wait_for_requests
+
+      page.within('.diff-discussions') do
+        expect(page).not_to have_content('Applied')
+
+        click_button('Apply suggestion')
+        wait_for_requests
+
+        expect(page).to have_content('Applied')
       end
     end
   end
diff --git a/spec/frontend/vue_shared/components/markdown/suggestion_diff_row_spec.js b/spec/frontend/vue_shared/components/markdown/suggestion_diff_row_spec.js
new file mode 100644
index 00000000000..866d6eb05c6
--- /dev/null
+++ b/spec/frontend/vue_shared/components/markdown/suggestion_diff_row_spec.js
@@ -0,0 +1,98 @@
+import { shallowMount, createLocalVue } from '@vue/test-utils';
+import SuggestionDiffRow from '~/vue_shared/components/markdown/suggestion_diff_row.vue';
+
+const oldLine = {
+  can_receive_suggestion: false,
+  line_code: null,
+  meta_data: null,
+  new_line: null,
+  old_line: 5,
+  rich_text: '-oldtext',
+  text: '-oldtext',
+  type: 'old',
+};
+
+const newLine = {
+  can_receive_suggestion: false,
+  line_code: null,
+  meta_data: null,
+  new_line: 6,
+  old_line: null,
+  rich_text: '-newtext',
+  text: '-newtext',
+  type: 'new',
+};
+
+describe(SuggestionDiffRow.name, () => {
+  let wrapper;
+
+  const factory = (options = {}) => {
+    const localVue = createLocalVue();
+
+    wrapper = shallowMount(SuggestionDiffRow, {
+      localVue,
+      ...options,
+    });
+  };
+
+  const findOldLineWrapper = () => wrapper.find('.old_line');
+  const findNewLineWrapper = () => wrapper.find('.new_line');
+
+  afterEach(() => {
+    wrapper.destroy();
+  });
+
+  it('renders correctly', () => {
+    factory({
+      propsData: {
+        line: oldLine,
+      },
+    });
+
+    expect(wrapper.is('.line_holder')).toBe(true);
+  });
+
+  describe('when passed line has type old', () => {
+    beforeEach(() => {
+      factory({
+        propsData: {
+          line: oldLine,
+        },
+      });
+    });
+
+    it('has old class when line has type old', () => {
+      expect(wrapper.find('td').classes()).toContain('old');
+    });
+
+    it('has old line number rendered', () => {
+      expect(findOldLineWrapper().text()).toBe('5');
+    });
+
+    it('has no new line number rendered', () => {
+      expect(findNewLineWrapper().text()).toBe('');
+    });
+  });
+
+  describe('when passed line has type new', () => {
+    beforeEach(() => {
+      factory({
+        propsData: {
+          line: newLine,
+        },
+      });
+    });
+
+    it('has new class when line has type new', () => {
+      expect(wrapper.find('td').classes()).toContain('new');
+    });
+
+    it('has no old line number rendered', () => {
+      expect(findOldLineWrapper().text()).toBe('');
+    });
+
+    it('has no new line number rendered', () => {
+      expect(findNewLineWrapper().text()).toBe('6');
+    });
+  });
+});
diff --git a/spec/javascripts/notes/mock_data.js b/spec/javascripts/notes/mock_data.js
index 348743081eb..1df5cf9ef68 100644
--- a/spec/javascripts/notes/mock_data.js
+++ b/spec/javascripts/notes/mock_data.js
@@ -44,8 +44,7 @@ export const noteableDataMock = {
   milestone: null,
   milestone_id: null,
   moved_to_id: null,
-  preview_note_path:
-    '/gitlab-org/gitlab-ce/preview_markdown?quick_actions_target_id=98&quick_actions_target_type=Issue',
+  preview_note_path: '/gitlab-org/gitlab-ce/preview_markdown?target_id=98&target_type=Issue',
   project_id: 2,
   state: 'opened',
   time_estimate: 0,
@@ -347,8 +346,7 @@ export const loggedOutnoteableData = {
   },
   noteable_note_url: '/group/project/merge_requests/1#note_1',
   create_note_path: '/gitlab-org/gitlab-ce/notes?target_id=98&target_type=issue',
-  preview_note_path:
-    '/gitlab-org/gitlab-ce/preview_markdown?quick_actions_target_id=98&quick_actions_target_type=Issue',
+  preview_note_path: '/gitlab-org/gitlab-ce/preview_markdown?target_id=98&target_type=Issue',
 };
 
 export const collapseNotesMock = [
diff --git a/spec/javascripts/vue_shared/components/markdown/header_spec.js b/spec/javascripts/vue_shared/components/markdown/header_spec.js
index e733a95288e..d4be2451f0b 100644
--- a/spec/javascripts/vue_shared/components/markdown/header_spec.js
+++ b/spec/javascripts/vue_shared/components/markdown/header_spec.js
@@ -98,7 +98,7 @@ describe('Markdown field header component', () => {
   it('renders suggestion template', () => {
     vm.lineContent = 'Some content';
 
-    expect(vm.mdSuggestion).toEqual('```suggestion\n{text}\n```');
+    expect(vm.mdSuggestion).toEqual('```suggestion:-0+0\n{text}\n```');
   });
 
   it('does not render suggestion button if `canSuggest` is set to false', () => {
diff --git a/spec/javascripts/vue_shared/components/markdown/suggestion_diff_spec.js b/spec/javascripts/vue_shared/components/markdown/suggestion_diff_spec.js
index f87c2a92f47..ea74cb9eb21 100644
--- a/spec/javascripts/vue_shared/components/markdown/suggestion_diff_spec.js
+++ b/spec/javascripts/vue_shared/components/markdown/suggestion_diff_spec.js
@@ -1,21 +1,50 @@
 import Vue from 'vue';
 import SuggestionDiffComponent from '~/vue_shared/components/markdown/suggestion_diff.vue';
+import { selectDiffLines } from '~/vue_shared/components/lib/utils/diff_utils';
 
 const MOCK_DATA = {
   canApply: true,
-  newLines: [
-    { content: 'Line 1\n', lineNumber: 1 },
-    { content: 'Line 2\n', lineNumber: 2 },
-    { content: 'Line 3\n', lineNumber: 3 },
-  ],
-  fromLine: 1,
-  fromContent: 'Old content',
   suggestion: {
     id: 1,
+    diff_lines: [
+      {
+        can_receive_suggestion: false,
+        line_code: null,
+        meta_data: null,
+        new_line: null,
+        old_line: 5,
+        rich_text: '-test',
+        text: '-test',
+        type: 'old',
+      },
+      {
+        can_receive_suggestion: true,
+        line_code: null,
+        meta_data: null,
+        new_line: 5,
+        old_line: null,
+        rich_text: '+new test',
+        text: '+new test',
+        type: 'new',
+      },
+      {
+        can_receive_suggestion: true,
+        line_code: null,
+        meta_data: null,
+        new_line: 5,
+        old_line: null,
+        rich_text: '+new test2',
+        text: '+new test2',
+        type: 'new',
+      },
+    ],
   },
   helpPagePath: 'path_to_docs',
 };
 
+const lines = selectDiffLines(MOCK_DATA.suggestion.diff_lines);
+const newLines = lines.filter(line => line.type === 'new');
+
 describe('Suggestion Diff component', () => {
   let vm;
 
@@ -39,30 +68,23 @@ describe('Suggestion Diff component', () => {
     });
 
     it('renders the oldLineNumber', () => {
-      const fromLine = vm.$el.querySelector('.qa-old-diff-line-number').innerHTML;
+      const fromLine = vm.$el.querySelector('.old_line').innerHTML;
 
-      expect(parseInt(fromLine, 10)).toBe(vm.fromLine);
+      expect(parseInt(fromLine, 10)).toBe(lines[0].old_line);
     });
 
     it('renders the oldLineContent', () => {
       const fromContent = vm.$el.querySelector('.line_content.old').innerHTML;
 
-      expect(fromContent.includes(vm.fromContent)).toBe(true);
-    });
-
-    it('renders the contents of newLines', () => {
-      const newLines = vm.$el.querySelectorAll('.line_holder.new');
-
-      newLines.forEach((line, i) => {
-        expect(newLines[i].innerHTML.includes(vm.newLines[i].content)).toBe(true);
-      });
+      expect(fromContent.includes(lines[0].text)).toBe(true);
     });
 
-    it('renders a line number for each line', () => {
-      const newLineNumbers = vm.$el.querySelectorAll('.qa-new-diff-line-number');
+    it('renders new lines', () => {
+      const newLinesElements = vm.$el.querySelectorAll('.line_holder.new');
 
-      newLineNumbers.forEach((line, i) => {
-        expect(newLineNumbers[i].innerHTML.includes(vm.newLines[i].lineNumber)).toBe(true);
+      newLinesElements.forEach((line, i) => {
+        expect(newLinesElements[i].innerHTML.includes(newLines[i].new_line)).toBe(true);
+        expect(newLinesElements[i].innerHTML.includes(newLines[i].text)).toBe(true);
       });
     });
   });
diff --git a/spec/javascripts/vue_shared/components/markdown/suggestions_spec.js b/spec/javascripts/vue_shared/components/markdown/suggestions_spec.js
index 33be63a3a1e..b7de40b4831 100644
--- a/spec/javascripts/vue_shared/components/markdown/suggestions_spec.js
+++ b/spec/javascripts/vue_shared/components/markdown/suggestions_spec.js
@@ -2,46 +2,52 @@ import Vue from 'vue';
 import SuggestionsComponent from '~/vue_shared/components/markdown/suggestions.vue';
 
 const MOCK_DATA = {
-  fromLine: 1,
-  fromContent: 'Old content',
-  suggestions: [],
+  suggestions: [
+    {
+      id: 1,
+      appliable: true,
+      applied: false,
+      current_user: {
+        can_apply: true,
+      },
+      diff_lines: [
+        {
+          can_receive_suggestion: false,
+          line_code: null,
+          meta_data: null,
+          new_line: null,
+          old_line: 5,
+          rich_text: '-test',
+          text: '-test',
+          type: 'old',
+        },
+        {
+          can_receive_suggestion: true,
+          line_code: null,
+          meta_data: null,
+          new_line: 5,
+          old_line: null,
+          rich_text: '+new test',
+          text: '+new test',
+          type: 'new',
+        },
+      ],
+    },
+  ],
   noteHtml: `
+      <div class="suggestion">
+      <div class="line">-oldtest</div>
+    </div>  
     <div class="suggestion">
-      <div class="line">Suggestion 1</div>
+      <div class="line">+newtest</div>
     </div>    
-    
-    <div class="suggestion">
-      <div class="line">Suggestion 2</div>
-    </div>
   `,
   isApplied: false,
   helpPagePath: 'path_to_docs',
 };
 
-const generateLine = content => {
-  const line = document.createElement('div');
-  line.className = 'line';
-  line.innerHTML = content;
-
-  return line;
-};
-
-const generateMockLines = () => {
-  const line1 = generateLine('Line 1');
-  const line2 = generateLine('Line 2');
-  const line3 = generateLine('- Line 3');
-  const container = document.createElement('div');
-
-  container.appendChild(line1);
-  container.appendChild(line2);
-  container.appendChild(line3);
-
-  return container;
-};
-
 describe('Suggestion component', () => {
   let vm;
-  let extractedLines;
   let diffTable;
 
   beforeEach(done => {
@@ -51,8 +57,7 @@ describe('Suggestion component', () => {
       propsData: MOCK_DATA,
     }).$mount();
 
-    extractedLines = vm.extractNewLines(generateMockLines());
-    diffTable = vm.generateDiff(extractedLines).$mount().$el;
+    diffTable = vm.generateDiff(0).$mount().$el;
 
     spyOn(vm, 'renderSuggestions');
     vm.renderSuggestions();
@@ -70,32 +75,8 @@ describe('Suggestion component', () => {
 
     it('renders suggestions', () => {
       expect(vm.renderSuggestions).toHaveBeenCalled();
-      expect(vm.$el.innerHTML.includes('Suggestion 1')).toBe(true);
-      expect(vm.$el.innerHTML.includes('Suggestion 2')).toBe(true);
-    });
-  });
-
-  describe('extractNewLines', () => {
-    it('extracts suggested lines', () => {
-      const expectedReturn = [
-        { content: 'Line 1\n', lineNumber: 1 },
-        { content: 'Line 2\n', lineNumber: 2 },
-        { content: '- Line 3\n', lineNumber: 3 },
-      ];
-
-      expect(vm.extractNewLines(generateMockLines())).toEqual(expectedReturn);
-    });
-
-    it('increments line number for each extracted line', () => {
-      expect(extractedLines[0].lineNumber).toEqual(1);
-      expect(extractedLines[1].lineNumber).toEqual(2);
-      expect(extractedLines[2].lineNumber).toEqual(3);
-    });
-
-    it('returns empty array if no lines are found', () => {
-      const el = document.createElement('div');
-
-      expect(vm.extractNewLines(el)).toEqual([]);
+      expect(vm.$el.innerHTML.includes('oldtest')).toBe(true);
+      expect(vm.$el.innerHTML.includes('newtest')).toBe(true);
     });
   });
 
@@ -109,17 +90,17 @@ describe('Suggestion component', () => {
     });
 
     it('generates a diff table that contains contents the suggested lines', () => {
-      extractedLines.forEach((line, i) => {
-        expect(diffTable.innerHTML.includes(extractedLines[i].content)).toBe(true);
+      MOCK_DATA.suggestions[0].diff_lines.forEach(line => {
+        const text = line.text.substring(1);
+
+        expect(diffTable.innerHTML.includes(text)).toBe(true);
       });
     });
 
     it('generates a diff table with the correct line number for each suggested line', () => {
-      const lines = diffTable.getElementsByClassName('qa-new-diff-line-number');
+      const lines = diffTable.querySelectorAll('.old_line');
 
-      expect([...lines][0].innerHTML).toBe('1');
-      expect([...lines][1].innerHTML).toBe('2');
-      expect([...lines][2].innerHTML).toBe('3');
+      expect(parseInt([...lines][0].innerHTML, 10)).toBe(5);
     });
   });
 });
diff --git a/spec/lib/banzai/suggestions_parser_spec.rb b/spec/lib/banzai/suggestions_parser_spec.rb
deleted file mode 100644
index 79658d710ce..00000000000
--- a/spec/lib/banzai/suggestions_parser_spec.rb
+++ /dev/null
@@ -1,32 +0,0 @@
-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Banzai::SuggestionsParser do
-  describe '.parse' do
-    it 'returns a list of suggestion contents' do
-      markdown = <<-MARKDOWN.strip_heredoc
-        ```suggestion
-          foo
-          bar
-        ```
-
-        ```
-          nothing
-        ```
-
-        ```suggestion
-          xpto
-          baz
-        ```
-
-        ```thing
-          this is not a suggestion, it's a thing
-        ```
-      MARKDOWN
-
-      expect(described_class.parse(markdown)).to eq(["  foo\n  bar",
-                                                     "  xpto\n  baz"])
-    end
-  end
-end
diff --git a/spec/lib/gitlab/diff/suggestion_spec.rb b/spec/lib/gitlab/diff/suggestion_spec.rb
index 71fd25df698..d7ca0e0a522 100644
--- a/spec/lib/gitlab/diff/suggestion_spec.rb
+++ b/spec/lib/gitlab/diff/suggestion_spec.rb
@@ -10,6 +10,16 @@ describe Gitlab::Diff::Suggestion do
                                             lines_above: above,
                                             lines_below: below)
     end
+
+    it 'returns diff lines with correct line numbers' do
+      diff_lines = suggestion.diff_lines
+
+      expect(diff_lines).to all(be_a(Gitlab::Diff::Line))
+
+      expected_diff_lines.each_with_index do |expected_line, index|
+        expect(diff_lines[index].to_hash).to include(expected_line)
+      end
+    end
   end
 
   let(:merge_request) { create(:merge_request) }
@@ -48,6 +58,18 @@ describe Gitlab::Diff::Suggestion do
       let(:expected_above) { line - 1 }
       let(:expected_below) { below }
       let(:expected_lines) { blob_lines_data(line - expected_above, line + expected_below) }
+      let(:expected_diff_lines) do
+        [
+          { old_pos: 1, new_pos: 1, type: 'old', text: "-require 'fileutils'" },
+          { old_pos: 2, new_pos: 1, type: 'old', text: "-require 'open3'" },
+          { old_pos: 3, new_pos: 1, type: 'old', text: "-" },
+          { old_pos: 4, new_pos: 1, type: 'old', text: "-module Popen" },
+          { old_pos: 5, new_pos: 1, type: 'old', text: "-  extend self" },
+          { old_pos: 6, new_pos: 1, type: 'old', text: "-" },
+          { old_pos: 7, new_pos: 1, type: 'new', text: "+# parsed suggestion content" },
+          { old_pos: 7, new_pos: 2, type: 'new', text: "+# with comments" }
+        ]
+      end
 
       it_behaves_like 'correct suggestion raw content'
     end
@@ -59,6 +81,47 @@ describe Gitlab::Diff::Suggestion do
       let(:expected_below) { below }
       let(:expected_above) { above }
       let(:expected_lines) { blob_lines_data(line - expected_above, line + expected_below) }
+      let(:expected_diff_lines) do
+        [
+          { old_pos: 4, new_pos: 4, type: "match", text: "@@ -4 +4" },
+          { old_pos: 4, new_pos: 4, type: "old", text: "-module Popen" },
+          { old_pos: 5, new_pos: 4, type: "old", text: "-  extend self" },
+          { old_pos: 6, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 7, new_pos: 4, type: "old", text: "-  def popen(cmd, path=nil)" },
+          { old_pos: 8, new_pos: 4, type: "old", text: "-    unless cmd.is_a?(Array)" },
+          { old_pos: 9, new_pos: 4, type: "old", text: "-      raise RuntimeError, \"System commands must be given as an array of strings\"" },
+          { old_pos: 10, new_pos: 4, type: "old", text: "-    end" },
+          { old_pos: 11, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 12, new_pos: 4, type: "old", text: "-    path ||= Dir.pwd" },
+          { old_pos: 13, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 14, new_pos: 4, type: "old", text: "-    vars = {" },
+          { old_pos: 15, new_pos: 4, type: "old", text: "-      \"PWD\" => path" },
+          { old_pos: 16, new_pos: 4, type: "old", text: "-    }" },
+          { old_pos: 17, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 18, new_pos: 4, type: "old", text: "-    options = {" },
+          { old_pos: 19, new_pos: 4, type: "old", text: "-      chdir: path" },
+          { old_pos: 20, new_pos: 4, type: "old", text: "-    }" },
+          { old_pos: 21, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 22, new_pos: 4, type: "old", text: "-    unless File.directory?(path)" },
+          { old_pos: 23, new_pos: 4, type: "old", text: "-      FileUtils.mkdir_p(path)" },
+          { old_pos: 24, new_pos: 4, type: "old", text: "-    end" },
+          { old_pos: 25, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 26, new_pos: 4, type: "old", text: "-    @cmd_output = \"\"" },
+          { old_pos: 27, new_pos: 4, type: "old", text: "-    @cmd_status = 0" },
+          { old_pos: 28, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 29, new_pos: 4, type: "old", text: "-    Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|" },
+          { old_pos: 30, new_pos: 4, type: "old", text: "-      @cmd_output << stdout.read" },
+          { old_pos: 31, new_pos: 4, type: "old", text: "-      @cmd_output << stderr.read" },
+          { old_pos: 32, new_pos: 4, type: "old", text: "-      @cmd_status = wait_thr.value.exitstatus" },
+          { old_pos: 33, new_pos: 4, type: "old", text: "-    end" },
+          { old_pos: 34, new_pos: 4, type: "old", text: "-" },
+          { old_pos: 35, new_pos: 4, type: "old", text: "-    return @cmd_output, @cmd_status" },
+          { old_pos: 36, new_pos: 4, type: "old", text: "-  end" },
+          { old_pos: 37, new_pos: 4, type: "old", text: "-end" },
+          { old_pos: 38, new_pos: 4, type: "new", text: "+# parsed suggestion content" },
+          { old_pos: 38, new_pos: 5, type: "new", text: "+# with comments" }
+        ]
+      end
 
       it_behaves_like 'correct suggestion raw content'
     end
@@ -70,17 +133,19 @@ describe Gitlab::Diff::Suggestion do
       let(:expected_below) { below }
       let(:expected_above) { above }
       let(:expected_lines) { blob_lines_data(line - expected_above, line + expected_below) }
-
-      it_behaves_like 'correct suggestion raw content'
-    end
-
-    context 'when no extra lines (single-line suggestion)' do
-      let(:line) { 5 }
-      let(:above) { 0 }
-      let(:below) { 0 }
-      let(:expected_below) { below }
-      let(:expected_above) { above }
-      let(:expected_lines) { blob_lines_data(line - expected_above, line + expected_below) }
+      let(:expected_diff_lines) do
+        [
+          { old_pos: 3, new_pos: 3, type: "match", text: "@@ -3 +3" },
+          { old_pos: 3, new_pos: 3, type: "old", text: "-" },
+          { old_pos: 4, new_pos: 3, type: "old", text: "-module Popen" },
+          { old_pos: 5, new_pos: 3, type: "old", text: "-  extend self" },
+          { old_pos: 6, new_pos: 3, type: "old", text: "-" },
+          { old_pos: 7, new_pos: 3, type: "old", text: "-  def popen(cmd, path=nil)" },
+          { old_pos: 8, new_pos: 3, type: "old", text: "-    unless cmd.is_a?(Array)" },
+          { old_pos: 9, new_pos: 3, type: "new", text: "+# parsed suggestion content" },
+          { old_pos: 9, new_pos: 4, type: "new", text: "+# with comments" }
+        ]
+      end
 
       it_behaves_like 'correct suggestion raw content'
     end
diff --git a/spec/lib/gitlab/diff/suggestions_parser_spec.rb b/spec/lib/gitlab/diff/suggestions_parser_spec.rb
index 1119ea04995..1f2af42f6e7 100644
--- a/spec/lib/gitlab/diff/suggestions_parser_spec.rb
+++ b/spec/lib/gitlab/diff/suggestions_parser_spec.rb
@@ -69,5 +69,66 @@ describe Gitlab::Diff::SuggestionsParser do
                                                   lines_below: 0)
       end
     end
+
+    context 'multi-line suggestions' do
+      let(:markdown) do
+        <<-MARKDOWN.strip_heredoc
+          ```suggestion:-2+1
+            # above and below
+          ```
+
+          ```
+            nothing
+          ```
+
+          ```suggestion:-3
+            # only above
+          ```
+
+          ```suggestion:+3
+            # only below
+          ```
+
+          ```thing
+            this is not a suggestion, it's a thing
+          ```
+        MARKDOWN
+      end
+
+      it 'returns a list of Gitlab::Diff::Suggestion' do
+        expect(subject).to all(be_a(Gitlab::Diff::Suggestion))
+        expect(subject.size).to eq(3)
+      end
+
+      it 'suggestion with above and below param has correct data' do
+        from_line = position.new_line - 2
+        to_line = position.new_line + 1
+
+        expect(subject.first.to_hash).to include(from_content: blob_lines_data(from_line, to_line),
+                                                 to_content: "  # above and below\n",
+                                                 lines_above: 2,
+                                                 lines_below: 1)
+      end
+
+      it 'suggestion with above param has correct data' do
+        from_line = position.new_line - 3
+        to_line = position.new_line
+
+        expect(subject.second.to_hash).to eq(from_content: blob_lines_data(from_line, to_line),
+                                             to_content: "  # only above\n",
+                                             lines_above: 3,
+                                             lines_below: 0)
+      end
+
+      it 'suggestion with below param has correct data' do
+        from_line = position.new_line
+        to_line = position.new_line + 3
+
+        expect(subject.third.to_hash).to eq(from_content: blob_lines_data(from_line, to_line),
+                                            to_content: "  # only below\n",
+                                            lines_above: 0,
+                                            lines_below: 3)
+      end
+    end
   end
 end
diff --git a/spec/models/suggestion_spec.rb b/spec/models/suggestion_spec.rb
index cafc725dddb..8d4e9070b19 100644
--- a/spec/models/suggestion_spec.rb
+++ b/spec/models/suggestion_spec.rb
@@ -21,6 +21,22 @@ describe Suggestion do
     end
   end
 
+  describe '#diff_lines' do
+    let(:suggestion) { create(:suggestion, :content_from_repo) }
+
+    it 'returns parsed diff lines' do
+      expected_diff_lines = Gitlab::Diff::SuggestionDiff.new(suggestion).diff_lines
+      diff_lines = suggestion.diff_lines
+
+      expect(diff_lines.size).to eq(expected_diff_lines.size)
+      expect(diff_lines).to all(be_a(Gitlab::Diff::Line))
+
+      expected_diff_lines.each_with_index do |expected_line, index|
+        expect(diff_lines[index].to_hash).to eq(expected_line.to_hash)
+      end
+    end
+  end
+
   describe '#appliable?' do
     context 'when note does not support suggestions' do
       it 'returns false' do
diff --git a/spec/serializers/suggestion_entity_spec.rb b/spec/serializers/suggestion_entity_spec.rb
index d38fc2b132b..d282a7f9c7a 100644
--- a/spec/serializers/suggestion_entity_spec.rb
+++ b/spec/serializers/suggestion_entity_spec.rb
@@ -13,8 +13,7 @@ describe SuggestionEntity do
   subject { entity.as_json }
 
   it 'exposes correct attributes' do
-    expect(subject).to include(:id, :from_line, :to_line, :appliable,
-                               :applied, :from_content, :to_content)
+    expect(subject.keys).to match_array([:id, :appliable, :applied, :diff_lines, :current_user])
   end
 
   it 'exposes current user abilities' do
diff --git a/spec/services/preview_markdown_service_spec.rb b/spec/services/preview_markdown_service_spec.rb
index 85515d548a7..a1d31464e07 100644
--- a/spec/services/preview_markdown_service_spec.rb
+++ b/spec/services/preview_markdown_service_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe PreviewMarkdownService do
   let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  let(:project) { create(:project, :repository) }
 
   before do
     project.add_developer(user)
@@ -20,23 +20,72 @@ describe PreviewMarkdownService do
   end
 
   describe 'suggestions' do
-    let(:params) { { text: "```suggestion\nfoo\n```", preview_suggestions: preview_suggestions } }
+    let(:merge_request) do
+      create(:merge_request, target_project: project, source_project: project)
+    end
+    let(:text) { "```suggestion\nfoo\n```" }
+    let(:params) do
+      suggestion_params.merge(text: text,
+                              target_type: 'MergeRequest',
+                              target_id: merge_request.iid)
+    end
     let(:service) { described_class.new(project, user, params) }
 
     context 'when preview markdown param is present' do
-      let(:preview_suggestions) { true }
+      let(:path) { "files/ruby/popen.rb" }
+      let(:line) { 10 }
+      let(:diff_refs) { merge_request.diff_refs }
+
+      let(:suggestion_params) do
+        {
+          preview_suggestions: true,
+          file_path: path,
+          line: line,
+          base_sha: diff_refs.base_sha,
+          start_sha: diff_refs.start_sha,
+          head_sha: diff_refs.head_sha
+        }
+      end
+
+      it 'returns suggestions referenced in text' do
+        position = Gitlab::Diff::Position.new(new_path: path,
+                                              new_line: line,
+                                              diff_refs: diff_refs)
+
+        expect(Gitlab::Diff::SuggestionsParser)
+          .to receive(:parse)
+          .with(text, position: position, project: merge_request.project)
+          .and_call_original
 
-      it 'returns users referenced in text' do
         result = service.execute
 
-        expect(result[:suggestions]).to eq(['foo'])
+        expect(result[:suggestions]).to all(be_a(Gitlab::Diff::Suggestion))
+      end
+
+      context 'when user is not authorized' do
+        let(:another_user) { create(:user) }
+        let(:service) { described_class.new(project, another_user, params) }
+
+        before do
+          project.add_guest(another_user)
+        end
+
+        it 'returns no suggestions' do
+          result = service.execute
+
+          expect(result[:suggestions]).to be_empty
+        end
       end
     end
 
     context 'when preview markdown param is not present' do
-      let(:preview_suggestions) { false }
+      let(:suggestion_params) do
+        {
+          preview_suggestions: false
+        }
+      end
 
-      it 'returns users referenced in text' do
+      it 'returns suggestions referenced in text' do
         result = service.execute
 
         expect(result[:suggestions]).to eq([])
@@ -49,8 +98,8 @@ describe PreviewMarkdownService do
     let(:params) do
       {
         text: "Please do it\n/assign #{user.to_reference}",
-        quick_actions_target_type: 'Issue',
-        quick_actions_target_id: issue.id
+        target_type: 'Issue',
+        target_id: issue.id
       }
     end
     let(:service) { described_class.new(project, user, params) }
@@ -72,7 +121,7 @@ describe PreviewMarkdownService do
     let(:params) do
       {
         text: "My work\n/estimate 2y",
-        quick_actions_target_type: 'MergeRequest'
+        target_type: 'MergeRequest'
       }
     end
     let(:service) { described_class.new(project, user, params) }
@@ -96,8 +145,8 @@ describe PreviewMarkdownService do
     let(:params) do
       {
         text: "My work\n/tag v1.2.3 Stable release",
-        quick_actions_target_type: 'Commit',
-        quick_actions_target_id: commit.id
+        target_type: 'Commit',
+        target_id: commit.id
       }
     end
     let(:service) { described_class.new(project, user, params) }
diff --git a/spec/services/suggestions/apply_service_spec.rb b/spec/services/suggestions/apply_service_spec.rb
index 80b5dcac6c7..7732767137c 100644
--- a/spec/services/suggestions/apply_service_spec.rb
+++ b/spec/services/suggestions/apply_service_spec.rb
@@ -51,6 +51,10 @@ describe Suggestions::ApplyService do
                                diff_refs: merge_request.diff_refs)
   end
 
+  let(:diff_note) do
+    create(:diff_note_on_merge_request, noteable: merge_request, position: position, project: project)
+  end
+
   let(:suggestion) do
     create(:suggestion, :content_from_repo, note: diff_note,
                                             to_content: "      raise RuntimeError, 'Explosion'\n      # explosion?\n")
@@ -108,12 +112,6 @@ describe Suggestions::ApplyService do
                                target_project: project)
       end
 
-      let!(:diff_note) do
-        create(:diff_note_on_merge_request, noteable: merge_request,
-                                            position: position,
-                                            project: project)
-      end
-
       before do
         project.add_maintainer(user)
       end
@@ -192,11 +190,6 @@ describe Suggestions::ApplyService do
           CONTENT
         end
 
-        let(:merge_request) do
-          create(:merge_request, source_project: project,
-                                 target_project: project)
-        end
-
         def create_suggestion(diff, old_line: nil, new_line: nil, from_content:, to_content:, path:)
           position = Gitlab::Diff::Position.new(old_path: path,
                                                 new_path: path,
@@ -291,6 +284,55 @@ describe Suggestions::ApplyService do
           expect(suggestion_2_diff.strip).to eq(expected_suggestion_2_diff.strip)
         end
       end
+
+      context 'multi-line suggestion' do
+        let(:expected_content) do
+          <<~CONTENT
+            require 'fileutils'
+            require 'open3'
+
+            module Popen
+              extend self
+
+            # multi
+            # line
+
+                vars = {
+                  "PWD" => path
+                }
+
+                options = {
+                  chdir: path
+                }
+
+                unless File.directory?(path)
+                  FileUtils.mkdir_p(path)
+                end
+
+                @cmd_output = ""
+                @cmd_status = 0
+
+                Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|
+                  @cmd_output << stdout.read
+                  @cmd_output << stderr.read
+                  @cmd_status = wait_thr.value.exitstatus
+                end
+
+                return @cmd_output, @cmd_status
+              end
+            end
+          CONTENT
+        end
+
+        let(:suggestion) do
+          create(:suggestion, :content_from_repo, note: diff_note,
+                                                  lines_above: 2,
+                                                  lines_below: 3,
+                                                  to_content: "# multi\n# line\n")
+        end
+
+        it_behaves_like 'successfully creates commit and updates suggestion'
+      end
     end
 
     context 'fork-project' do