From 20d70859aa79b21b8a432d38ad1f113e434b4fc9 Mon Sep 17 00:00:00 2001
From: James Allen <james@sharelatex.com>
Date: Mon, 3 Mar 2014 17:39:59 +0000
Subject: [PATCH] Create buildDiff function

---
 .../app/coffee/DiffGenerator.coffee           |  4 +++
 .../DiffGenerator/DiffGeneratorTests.coffee   | 28 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/services/track-changes/app/coffee/DiffGenerator.coffee b/services/track-changes/app/coffee/DiffGenerator.coffee
index 9ea4682e31..fdec79d6f4 100644
--- a/services/track-changes/app/coffee/DiffGenerator.coffee
+++ b/services/track-changes/app/coffee/DiffGenerator.coffee
@@ -28,6 +28,10 @@ module.exports = DiffGenerator =
 		return content
 
 	buildDiff: (initialContent, updates) ->
+		diff = [ u: initialContent ]
+		for update in updates
+			diff = DiffGenerator.applyUpdateToDiff diff, update
+		return diff
 
 	applyUpdateToDiff: (diff, update) ->
 		position = 0
diff --git a/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee b/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee
index 47c4561074..18b2e637e1 100644
--- a/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee
+++ b/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee
@@ -50,6 +50,34 @@ describe "DiffGenerator", ->
 			rewoundContent = @DiffGenerator.rewindUpdates content, updates
 			rewoundContent.should.equal "aaa"
 
+	describe "buildDiff", ->
+		beforeEach ->
+			@diff = [ u: "mock-diff" ]
+			@content = "Hello world"
+			@updates = [
+				{ i: "mock-update-1" }
+				{ i: "mock-update-2" }
+				{ i: "mock-update-3" }
+			]
+			@DiffGenerator.applyUpdateToDiff = sinon.stub().returns(@diff)
+			@result = @DiffGenerator.buildDiff(@content, @updates)
+
+		it "should return the diff", ->
+			@result.should.deep.equal @diff
+
+		it "should build the content into an initial diff", ->
+			@DiffGenerator.applyUpdateToDiff
+				.calledWith([{
+					u: @content
+				}], @updates[0])
+				.should.equal true
+
+		it "should apply each update", ->
+			for update in @updates
+				@DiffGenerator.applyUpdateToDiff
+					.calledWith(sinon.match.any, update)
+					.should.equal true
+
 	describe "applyUpdateToDiff", ->
 		describe "an insert", ->
 			it "should insert into the middle of (u)nchanged text", ->