diff --git a/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteController.coffee b/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteController.coffee
index beac6f2b45..bb9e013abe 100644
--- a/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteController.coffee
+++ b/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteController.coffee
@@ -10,19 +10,19 @@ module.exports = CollaboratorsInviteController =
 	inviteToProject: (req, res, next) ->
 		projectId = req.params.Project_id
 		email = req.body.email
-		sendingUserId = req.session?.user_id
+		sendingUserId = req.session?.user?._id
 		logger.log {projectId, email, sendingUserId}, "inviting to project"
-		LimitationsManager.canAddXCollaborators project_id, 1, (error, allowed) =>
+		LimitationsManager.canAddXCollaborators projectId, 1, (error, allowed) =>
 			return next(error) if error?
 			if !allowed
 				logger.log {projectId, email, sendingUserId}, "not allowed to invite more users to project"
-				return res.json {}
+				return res.json {inviteId: null}
 			{email, privileges} = req.body
 			email = mimelib.parseAddresses(email or "")[0]?.address?.toLowerCase()
 			if !email? or email == ""
 				logger.log {projectId, email, sendingUserId}, "invalid email address"
-				return res.status(400).send("invalid email address")
-			CollaboratorsInviteHandler.inviteToProject projectId, sendingUserId, email, priveleges, (err, invite) ->
+				return res.sendStatus(400)
+			CollaboratorsInviteHandler.inviteToProject projectId, sendingUserId, email, privileges, (err, invite) ->
 				if err?
 					logger.err {projectId, email, sendingUserId}, "error creating project invite"
 					return next(err)
@@ -37,7 +37,7 @@ module.exports = CollaboratorsInviteController =
 			if err?
 				logger.err {projectId, inviteId}, "error revoking invite"
 				return next(err)
-			res.status(201).send()
+			res.sendStatus(201)
 
 	viewInvite: (req, res, next) ->
 		projectId = req.params.Project_id
@@ -49,7 +49,7 @@ module.exports = CollaboratorsInviteController =
 				return next(err)
 			if !invite
 				logger.log {projectId, token}, "no invite found for token"
-				return res.redirect("/")
+				return res.sendStatus(404)
 			res.render "project/invite", {invite}
 
 	acceptInvite: (req, res, next) ->
@@ -59,6 +59,6 @@ module.exports = CollaboratorsInviteController =
 		logger.log {projectId, inviteId}, "accepting invite"
 		CollaboratorsInviteHandler.acceptInvite projectId, inviteId, currentUser, (err) ->
 			if err?
-				logger.err {projectId, token}, "error getting invite by token"
+				logger.err {projectId, inviteId}, "error getting invite by token"
 				return next(err)
-			rest.status(201).send()
+			res.sendStatus(201)
diff --git a/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteHandler.coffee b/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteHandler.coffee
index f22bcb4c4f..2d9932c093 100644
--- a/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteHandler.coffee
+++ b/services/web/app/coffee/Features/Collaborators/CollaboratorsInviteHandler.coffee
@@ -11,7 +11,7 @@ Errors = require "../Errors/Errors"
 
 module.experts = CollaboratorsInviteHandler =
 
-	inviteToProject: (projectId, sendingUserId, email, priveleges, callback=(err,invite)->) ->
+	inviteToProject: (projectId, sendingUserId, email, privileges, callback=(err,invite)->) ->
 
 	revokeInvite: (projectId, inviteId, callback=(err)->) ->
 
diff --git a/services/web/test/UnitTests/coffee/Collaborators/CollaboratorsInviteControllerTests.coffee b/services/web/test/UnitTests/coffee/Collaborators/CollaboratorsInviteControllerTests.coffee
index fb9e77f952..3a7ad86761 100644
--- a/services/web/test/UnitTests/coffee/Collaborators/CollaboratorsInviteControllerTests.coffee
+++ b/services/web/test/UnitTests/coffee/Collaborators/CollaboratorsInviteControllerTests.coffee
@@ -18,12 +18,106 @@ describe "CollaboratorsInviteController", ->
 			'../Subscription/LimitationsManager' : @LimitationsManager = {}
 			'../Project/ProjectEditorHandler' : @ProjectEditorHandler = {}
 			'../User/UserGetter': @UserGetter = {}
+			'logger-sharelatex': @logger = {err: sinon.stub(), error: sinon.stub(), log: sinon.stub()}
 		@res = new MockResponse()
 		@req = new MockRequest()
 
 		@project_id = "project-id-123"
 		@callback = sinon.stub()
 
+	describe 'inviteToProject', ->
+
+		beforeEach ->
+			@targetEmail = "user@example.com"
+			@req.params =
+				Project_id: @project_id
+			@req.session =
+				user: _id: @current_user_id = "current-user-id"
+			@req.body =
+				email: @targetEmail
+				privileges: @privileges = "readAndWrite"
+			@res.json = sinon.stub()
+			@res.sendStatus = sinon.stub()
+			@invite = {
+				_id: ObjectId(),
+				token: "htnseuthaouse",
+				sendingUserId: @current_user_id,
+				projectId: @targetEmail,
+				targetEmail: 'user@example.com'
+				createdAt: new Date(),
+				expiresAt: new Date()
+			}
+			@LimitationsManager.canAddXCollaborators = sinon.stub().callsArgWith(2, null, true)
+			@CollaboratorsInviteHandler.inviteToProject = sinon.stub().callsArgWith(4, null, @invite)
+			@callback = sinon.stub()
+			@next = sinon.stub()
+
+		describe 'when all goes well', ->
+
+			beforeEach ->
+				@LimitationsManager.canAddXCollaborators = sinon.stub().callsArgWith(2, null, true)
+				@CollaboratorsInviteController.inviteToProject @req, @res, @next
+
+			it 'should produce json response', ->
+				@res.json.callCount.should.equal 1
+				({inviteId: @invite._id}).should.deep.equal(@res.json.firstCall.args[0])
+
+			it 'should have called canAddXCollaborators', ->
+				@LimitationsManager.canAddXCollaborators.callCount.should.equal 1
+				@LimitationsManager.canAddXCollaborators.calledWith(@project_id).should.equal true
+
+			it 'should have called inviteToProject', ->
+				@CollaboratorsInviteHandler.inviteToProject.callCount.should.equal 1
+				@CollaboratorsInviteHandler.inviteToProject.calledWith(@project_id,@current_user_id,@targetEmail,@privileges).should.equal true
+
+		describe 'when the user is not allowed to add more collaborators', ->
+
+			beforeEach ->
+				@LimitationsManager.canAddXCollaborators = sinon.stub().callsArgWith(2, null, false)
+				@CollaboratorsInviteController.inviteToProject @req, @res, @next
+
+			it 'should produce json response without inviteId', ->
+				@res.json.callCount.should.equal 1
+				({inviteId: null}).should.deep.equal(@res.json.firstCall.args[0])
+
+			it 'should not have called inviteToProject', ->
+				@CollaboratorsInviteHandler.inviteToProject.callCount.should.equal 0
+
+		describe 'when canAddXCollaborators produces an error', ->
+
+			beforeEach ->
+				@err = new Error('woops')
+				@LimitationsManager.canAddXCollaborators = sinon.stub().callsArgWith(2, @err)
+				@CollaboratorsInviteController.inviteToProject @req, @res, @next
+
+			it 'should call next with an error', ->
+				@next.callCount.should.equal 1
+				@next.calledWith(@err).should.equal true
+
+			it 'should not have called inviteToProject', ->
+				@CollaboratorsInviteHandler.inviteToProject.callCount.should.equal 0
+
+		describe 'when inviteToProject produces an error', ->
+
+			beforeEach ->
+				@err = new Error('woops')
+				@CollaboratorsInviteHandler.inviteToProject = sinon.stub().callsArgWith(4, @err)
+				@CollaboratorsInviteController.inviteToProject @req, @res, @next
+
+			it 'should call next with an error', ->
+				@next.callCount.should.equal 1
+				@next.calledWith(@err).should.equal true
+
+			it 'should have called canAddXCollaborators', ->
+				@LimitationsManager.canAddXCollaborators.callCount.should.equal 1
+				@LimitationsManager.canAddXCollaborators.calledWith(@project_id).should.equal true
+
+			it 'should have called inviteToProject', ->
+				@CollaboratorsInviteHandler.inviteToProject.callCount.should.equal 1
+				@CollaboratorsInviteHandler.inviteToProject.calledWith(@project_id,@current_user_id,@targetEmail,@privileges).should.equal true
+
+	##
+
 	describe "viewInvite", ->
 
 		beforeEach ->
@@ -33,6 +127,7 @@ describe "CollaboratorsInviteController", ->
 			@req.session =
 				user: _id: @current_user_id = "current-user-id"
 			@res.render = sinon.stub()
+			@res.sendStatus = sinon.stub()
 			@invite = {
 				_id: ObjectId(),
 				token: "htnseuthaouse",
@@ -54,4 +149,129 @@ describe "CollaboratorsInviteController", ->
 
 			it 'should render the view template', ->
 				@res.render.callCount.should.equal 1
-				@res.render.firstCall.args[0].should.equal 'project/invite'
+				@res.render.calledWith('project/invite').should.equal true
+
+			it 'should not call next', ->
+				@next.callCount.should.equal 0
+
+			it 'should call getInviteByToken', ->
+				@CollaboratorsInviteHandler.getInviteByToken.callCount.should.equal 1
+
+		describe 'when the getInviteByToken produces an error', ->
+
+			beforeEach ->
+				@err = new Error('woops')
+				@CollaboratorsInviteHandler.getInviteByToken.callsArgWith(2, @err)
+				@CollaboratorsInviteController.viewInvite @req, @res, @next
+
+			it 'should call next with the error', ->
+				@next.callCount.should.equal 1
+				@next.calledWith(@err).should.equal true
+
+			it 'should call getInviteByToken', ->
+				@CollaboratorsInviteHandler.getInviteByToken.callCount.should.equal 1
+
+		describe 'when the getInviteByToken does not produce an invite', ->
+
+			beforeEach ->
+				@CollaboratorsInviteHandler.getInviteByToken.callsArgWith(2, null, null)
+				@CollaboratorsInviteController.viewInvite @req, @res, @next
+
+			it 'should produce a 404 response', ->
+				@res.sendStatus.callCount.should.equal 1
+				@res.sendStatus.calledWith(404).should.equal true
+
+			it 'should not render the view template', ->
+				@res.render.callCount.should.equal 0
+
+			it 'should not call next', ->
+				@next.callCount.should.equal 0
+
+			it 'should call getInviteByToken', ->
+				@CollaboratorsInviteHandler.getInviteByToken.callCount.should.equal 1
+
+	describe "revokeInvite", ->
+
+		beforeEach ->
+			@req.params =
+				Project_id: @project_id
+				invite_id: @invite_id = "thuseoautoh"
+			@req.session =
+				user: _id: @current_user_id = "current-user-id"
+			@res.render = sinon.stub()
+			@res.sendStatus = sinon.stub()
+			@CollaboratorsInviteHandler.revokeInvite = sinon.stub().callsArgWith(2, null)
+			@callback = sinon.stub()
+			@next = sinon.stub()
+
+		describe 'when revokeInvite does not produce an error', ->
+
+			beforeEach ->
+				@CollaboratorsInviteController.revokeInvite @req, @res, @next
+
+			it 'should produce a 201 response', ->
+				@res.sendStatus.callCount.should.equal 1
+				@res.sendStatus.calledWith(201).should.equal true
+
+			it 'should have called revokeInvite', ->
+				@CollaboratorsInviteHandler.revokeInvite.callCount.should.equal 1
+
+		describe 'when revokeInvite produces an error', ->
+
+			beforeEach ->
+				@err = new Error('woops')
+				@CollaboratorsInviteHandler.revokeInvite = sinon.stub().callsArgWith(2, @err)
+				@CollaboratorsInviteController.revokeInvite @req, @res, @next
+
+			it 'should not produce a 201 response', ->
+				@res.sendStatus.callCount.should.equal 0
+
+			it 'should call next with the error', ->
+				@next.callCount.should.equal 1
+				@next.calledWith(@err).should.equal true
+
+			it 'should have called revokeInvite', ->
+				@CollaboratorsInviteHandler.revokeInvite.callCount.should.equal 1
+
+	describe "acceptInvite", ->
+
+		beforeEach ->
+			@req.params =
+				Project_id: @project_id
+				invite_id: @invite_id = "thuseoautoh"
+			@req.session =
+				user: _id: @current_user_id = "current-user-id"
+			@res.render = sinon.stub()
+			@res.sendStatus = sinon.stub()
+			@CollaboratorsInviteHandler.acceptInvite = sinon.stub().callsArgWith(3, null)
+			@callback = sinon.stub()
+			@next = sinon.stub()
+
+		describe 'when acceptInvite does not produce an error', ->
+
+			beforeEach ->
+				@CollaboratorsInviteController.acceptInvite @req, @res, @next
+
+			it 'should produce a 201 response', ->
+				@res.sendStatus.callCount.should.equal 1
+				@res.sendStatus.calledWith(201).should.equal true
+
+			it 'should have called acceptInvite', ->
+				@CollaboratorsInviteHandler.acceptInvite.callCount.should.equal 1
+
+		describe 'when revokeInvite produces an error', ->
+
+			beforeEach ->
+				@err = new Error('woops')
+				@CollaboratorsInviteHandler.acceptInvite = sinon.stub().callsArgWith(3, @err)
+				@CollaboratorsInviteController.acceptInvite @req, @res, @next
+
+			it 'should not produce a 201 response', ->
+				@res.sendStatus.callCount.should.equal 0
+
+			it 'should call next with the error', ->
+				@next.callCount.should.equal 1
+				@next.calledWith(@err).should.equal true
+
+			it 'should have called acceptInvite', ->
+				@CollaboratorsInviteHandler.acceptInvite.callCount.should.equal 1