Add Snippet GraphQL API mutation endpoints

Added mutations for snippets GraphQL API endpoints.

app/graphql/mutations/snippets/base.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Snippets
+    class Base < BaseMutation
+      field :snippet,
+            Types::SnippetType,
+            null: true,
+            description: 'The snippet after mutation'
+
+      private
+
+      def find_object(id:)
+        GitlabSchema.object_from_id(id)
+      end
+
+      def authorized_resource?(snippet)
+        Ability.allowed?(context[:current_user], ability_for(snippet), snippet)
+      end
+
+      def ability_for(snippet)
+        "#{ability_name}_#{snippet.to_ability_name}".to_sym
+      end
+
+      def ability_name
+        raise NotImplementedError
+      end
+    end
+  end
+end

app/graphql/mutations/snippets/create.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Snippets
+    class Create < BaseMutation
+      include Mutations::ResolvesProject
+
+      graphql_name 'CreateSnippet'
+
+      field :snippet,
+            Types::SnippetType,
+            null: true,
+            description: 'The snippet after mutation'
+
+      argument :title, GraphQL::STRING_TYPE,
+               required: true,
+               description: 'Title of the snippet'
+
+      argument :file_name, GraphQL::STRING_TYPE,
+               required: false,
+               description: 'File name of the snippet'
+
+      argument :content, GraphQL::STRING_TYPE,
+               required: true,
+               description: 'Content of the snippet'
+
+      argument :description, GraphQL::STRING_TYPE,
+               required: false,
+               description: 'Description of the snippet'
+
+      argument :visibility_level, Types::VisibilityLevelsEnum,
+               description: 'The visibility level of the snippet',
+               required: true
+
+      argument :project_path, GraphQL::ID_TYPE,
+               required: false,
+               description: 'The project full path the snippet is associated with'
+
+      def resolve(args)
+        project_path = args.delete(:project_path)
+
+        if project_path.present?
+          project = find_project!(project_path: project_path)
+        elsif !can_create_personal_snippet?
+          raise_resource_not_avaiable_error!
+        end
+
+        snippet = CreateSnippetService.new(project,
+                                           context[:current_user],
+                                           args).execute
+
+        {
+          snippet: snippet.valid? ? snippet : nil,
+          errors: errors_on_object(snippet)
+        }
+      end
+
+      private
+
+      def find_project!(project_path:)
+        authorized_find!(full_path: project_path)
+      end
+
+      def find_object(full_path:)
+        resolve_project(full_path: full_path)
+      end
+
+      def authorized_resource?(project)
+        Ability.allowed?(context[:current_user], :create_project_snippet, project)
+      end
+
+      def can_create_personal_snippet?
+        Ability.allowed?(context[:current_user], :create_personal_snippet)
+      end
+    end
+  end
+end

app/graphql/mutations/snippets/destroy.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Snippets
+    class Destroy < Base
+      graphql_name 'DestroySnippet'
+
+      ERROR_MSG = 'Error deleting the snippet'
+
+      argument :id,
+               GraphQL::ID_TYPE,
+               required: true,
+               description: 'The global id of the snippet to destroy'
+
+      def resolve(id:)
+        snippet = authorized_find!(id: id)
+
+        result = snippet.destroy
+        errors = result ? [] : [ERROR_MSG]
+
+        {
+          errors: errors
+        }
+      end
+
+      private
+
+      def ability_name
+        "admin"
+      end
+    end
+  end
+end

app/graphql/mutations/snippets/update.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Snippets
+    class Update < Base
+      graphql_name 'UpdateSnippet'
+
+      argument :id,
+               GraphQL::ID_TYPE,
+               required: true,
+               description: 'The global id of the snippet to update'
+
+      argument :title, GraphQL::STRING_TYPE,
+               required: false,
+               description: 'Title of the snippet'
+
+      argument :file_name, GraphQL::STRING_TYPE,
+               required: false,
+               description: 'File name of the snippet'
+
+      argument :content, GraphQL::STRING_TYPE,
+               required: false,
+               description: 'Content of the snippet'
+
+      argument :description, GraphQL::STRING_TYPE,
+               required: false,
+               description: 'Description of the snippet'
+
+      argument :visibility_level, Types::VisibilityLevelsEnum,
+               description: 'The visibility level of the snippet',
+               required: false
+
+      def resolve(args)
+        snippet = authorized_find!(id: args.delete(:id))
+
+        result = UpdateSnippetService.new(snippet.project,
+                                          context[:current_user],
+                                          snippet,
+                                          args).execute
+
+        {
+          snippet: result ? snippet : snippet.reset,
+          errors: errors_on_object(snippet)
+        }
+      end
+
+      private
+
+      def ability_name
+        "update"
+      end
+    end
+  end
+end

app/graphql/resolvers/base_resolver.rb

@@ -2,6 +2,8 @@
 
 module Resolvers
   class BaseResolver < GraphQL::Schema::Resolver
+    extend ::Gitlab::Utils::Override
+
     def self.single
       @single ||= Class.new(self) do
         def resolve(**args)
@@ -36,5 +38,13 @@ module Resolvers
       # complexity difference is minimal in this case.
       [args[:iid], args[:iids]].any? ? 0 : 0.01
     end
+
+    override :object
+    def object
+      super.tap do |obj|
+        # If the field this resolver is used in is wrapped in a presenter, go back to it's subject
+        break obj.subject if obj.is_a?(Gitlab::View::Presenter::Base)
+      end
+    end
   end
 end

app/graphql/types/mutation_type.rb

@@ -25,6 +25,9 @@ module Types
     mount_mutation Mutations::Todos::MarkDone
     mount_mutation Mutations::Todos::Restore
     mount_mutation Mutations::Todos::MarkAllDone
+    mount_mutation Mutations::Snippets::Destroy
+    mount_mutation Mutations::Snippets::Update
+    mount_mutation Mutations::Snippets::Create
   end
 end
 

app/graphql/types/snippet_type.rb

@@ -44,8 +44,8 @@ module Types
           description: 'Description of the snippet',
           null: true
 
-    field :visibility, GraphQL::STRING_TYPE,
-          description: 'Visibility of the snippet',
+    field :visibility_level, Types::VisibilityLevelsEnum,
+          description: 'Visibility Level of the snippet',
           null: false
 
     field :created_at, Types::TimeType,

app/graphql/types/visibility_levels_enum.rb

+# frozen_string_literal: true
+
+module Types
+  class VisibilityLevelsEnum < BaseEnum
+    Gitlab::VisibilityLevel.string_options.each do |name, int_value|
+      value name.downcase, value: int_value
+    end
+  end
+end

app/presenters/snippet_presenter.rb

@@ -30,6 +30,6 @@ class SnippetPresenter < Gitlab::View::Presenter::Delegated
   end
 
   def ability_name(ability_prefix)
-    "#{ability_prefix}_#{snippet.class.underscore}".to_sym
+    "#{ability_prefix}_#{snippet.to_ability_name}".to_sym
   end
 end

changelogs/unreleased/fj-36079-snippet-graphql-endpoints-with-mutations.yml

+---
+title: Added Snippets GraphQL mutations
+merge_request: 20956
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -442,6 +442,66 @@ type CreateNotePayload {
   note: Note
 }
 
+"""
+Autogenerated input type of CreateSnippet
+"""
+input CreateSnippetInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Content of the snippet
+  """
+  content: String!
+
+  """
+  Description of the snippet
+  """
+  description: String
+
+  """
+  File name of the snippet
+  """
+  fileName: String
+
+  """
+  The project full path the snippet is associated with
+  """
+  projectPath: ID
+
+  """
+  Title of the snippet
+  """
+  title: String!
+
+  """
+  The visibility level of the snippet
+  """
+  visibilityLevel: VisibilityLevelsEnum!
+}
+
+"""
+Autogenerated return type of CreateSnippet
+"""
+type CreateSnippetPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Reasons why the mutation failed.
+  """
+  errors: [String!]!
+
+  """
+  The snippet after mutation
+  """
+  snippet: Snippet
+}
+
 type Design implements Noteable {
   diffRefs: DiffRefs!
 
@@ -861,6 +921,41 @@ type DestroyNotePayload {
   note: Note
 }
 
+"""
+Autogenerated input type of DestroySnippet
+"""
+input DestroySnippetInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  The global id of the snippet to destroy
+  """
+  id: ID!
+}
+
+"""
+Autogenerated return type of DestroySnippet
+"""
+type DestroySnippetPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Reasons why the mutation failed.
+  """
+  errors: [String!]!
+
+  """
+  The snippet after mutation
+  """
+  snippet: Snippet
+}
+
 type DetailedStatus {
   detailsPath: String!
   favicon: String!
@@ -3737,9 +3832,11 @@ type Mutation {
   createEpic(input: CreateEpicInput!): CreateEpicPayload
   createImageDiffNote(input: CreateImageDiffNoteInput!): CreateImageDiffNotePayload
   createNote(input: CreateNoteInput!): CreateNotePayload
+  createSnippet(input: CreateSnippetInput!): CreateSnippetPayload
   designManagementDelete(input: DesignManagementDeleteInput!): DesignManagementDeletePayload
   designManagementUpload(input: DesignManagementUploadInput!): DesignManagementUploadPayload
   destroyNote(input: DestroyNoteInput!): DestroyNotePayload
+  destroySnippet(input: DestroySnippetInput!): DestroySnippetPayload
   epicSetSubscription(input: EpicSetSubscriptionInput!): EpicSetSubscriptionPayload
   epicTreeReorder(input: EpicTreeReorderInput!): EpicTreeReorderPayload
   issueSetConfidential(input: IssueSetConfidentialInput!): IssueSetConfidentialPayload
@@ -3757,6 +3854,7 @@ type Mutation {
   toggleAwardEmoji(input: ToggleAwardEmojiInput!): ToggleAwardEmojiPayload
   updateEpic(input: UpdateEpicInput!): UpdateEpicPayload
   updateNote(input: UpdateNoteInput!): UpdateNotePayload
+  updateSnippet(input: UpdateSnippetInput!): UpdateSnippetPayload
 }
 
 """
@@ -5396,9 +5494,9 @@ type Snippet implements Noteable {
   userPermissions: SnippetPermissions!
 
   """
-  Visibility of the snippet
+  Visibility Level of the snippet
   """
-  visibility: String!
+  visibilityLevel: VisibilityLevelsEnum!
 
   """
   Web URL of the snippet
@@ -6120,6 +6218,66 @@ type UpdateNotePayload {
   note: Note
 }
 
+"""
+Autogenerated input type of UpdateSnippet
+"""
+input UpdateSnippetInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Content of the snippet
+  """
+  content: String
+
+  """
+  Description of the snippet
+  """
+  description: String
+
+  """
+  File name of the snippet
+  """
+  fileName: String
+
+  """
+  The global id of the snippet to update
+  """
+  id: ID!
+
+  """
+  Title of the snippet
+  """
+  title: String
+
+  """
+  The visibility level of the snippet
+  """
+  visibilityLevel: VisibilityLevelsEnum
+}
+
+"""
+Autogenerated return type of UpdateSnippet
+"""
+type UpdateSnippetPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Reasons why the mutation failed.
+  """
+  errors: [String!]!
+
+  """
+  The snippet after mutation
+  """
+  snippet: Snippet
+}
+
 scalar Upload
 
 type User {
@@ -6286,6 +6444,12 @@ type UserPermissions {
   createSnippet: Boolean!
 }
 
+enum VisibilityLevelsEnum {
+  internal
+  private
+  public
+}
+
 enum VisibilityScopesEnum {
   internal
   private

doc/api/graphql/reference/index.md

@@ -92,6 +92,14 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 | `errors` | String! => Array | Reasons why the mutation failed. |
 | `note` | Note | The note after mutation |
 
+### CreateSnippetPayload
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Reasons why the mutation failed. |
+| `snippet` | Snippet | The snippet after mutation |
+
 ### Design
 
 | Name  | Type  | Description |
@@ -145,6 +153,14 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 | `errors` | String! => Array | Reasons why the mutation failed. |
 | `note` | Note | The note after mutation |
 
+### DestroySnippetPayload
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Reasons why the mutation failed. |
+| `snippet` | Snippet | The snippet after mutation |
+
 ### DetailedStatus
 
 | Name  | Type  | Description |
@@ -802,7 +818,7 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 | `fileName` | String | File Name of the snippet |
 | `content` | String! | Content of the snippet |
 | `description` | String | Description of the snippet |
-| `visibility` | String! | Visibility of the snippet |
+| `visibilityLevel` | VisibilityLevelsEnum! | Visibility Level of the snippet |
 | `createdAt` | Time! | Timestamp this snippet was created |
 | `updatedAt` | Time! | Timestamp this snippet was updated |
 | `webUrl` | String! | Web URL of the snippet |
@@ -929,6 +945,14 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 | `errors` | String! => Array | Reasons why the mutation failed. |
 | `note` | Note | The note after mutation |
 
+### UpdateSnippetPayload
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Reasons why the mutation failed. |
+| `snippet` | Snippet | The snippet after mutation |
+
 ### User
 
 | Name  | Type  | Description |

ee/app/graphql/resolvers/epic_resolver.rb

@@ -88,7 +88,7 @@ module Resolvers
     # But that's the epic we need in order to scope the find to only children of this epic,
     # using the `parent_id`
     def parent
-      resolver_object if resolver_object.is_a?(EpicPresenter)
+      resolver_object if resolver_object.is_a?(Epic)
     end
 
     def group

lib/gitlab/graphql/authorize/authorize_resource.rb

@@ -6,6 +6,8 @@ module Gitlab
       module AuthorizeResource
         extend ActiveSupport::Concern
 
+        RESOURCE_ACCESS_ERROR = "The resource that you are attempting to access does not exist or you don't have permission to perform this action"
+
         class_methods do
           def required_permissions
             # If the `#authorize` call is used on multiple classes, we add the
@@ -38,8 +40,7 @@ module Gitlab
 
         def authorize!(object)
           unless authorized_resource?(object)
-            raise Gitlab::Graphql::Errors::ResourceNotAvailable,
-                  "The resource that you are attempting to access does not exist or you don't have permission to perform this action"
+            raise_resource_not_avaiable_error!
           end
         end
 
@@ -61,6 +62,10 @@ module Gitlab
             Ability.allowed?(current_user, ability, object, scope: :user)
           end
         end
+
+        def raise_resource_not_avaiable_error!
+          raise Gitlab::Graphql::Errors::ResourceNotAvailable, RESOURCE_ACCESS_ERROR
+        end
       end
     end
   end

spec/graphql/resolvers/base_resolver_spec.rb

@@ -8,8 +8,12 @@ describe Resolvers::BaseResolver do
   let(:resolver) do
     Class.new(described_class) do
       def resolve(**args)
+        process(object)
+
         [args, args]
       end
+
+      def process(obj); end
     end
   end
 
@@ -69,4 +73,26 @@ describe Resolvers::BaseResolver do
       expect(field.to_graphql.complexity.call({}, { sort: 'foo', iids: [1, 2, 3] }, 1)).to eq 3
     end
   end
+
+  describe '#object' do
+    let_it_be(:user) { create(:user) }
+
+    it 'returns object' do
+      expect_next_instance_of(resolver) do |r|
+        expect(r).to receive(:process).with(user)
+      end
+
+      resolve(resolver, obj: user)
+    end
+
+    context 'when object is a presenter' do
+      it 'returns presented object' do
+        expect_next_instance_of(resolver) do |r|
+          expect(r).to receive(:process).with(user)
+        end
+
+        resolve(resolver, obj: UserPresenter.new(user))
+      end
+    end
+  end
 end

spec/graphql/types/snippet_type_spec.rb

@@ -6,7 +6,7 @@ describe GitlabSchema.types['Snippet'] do
   it 'has the correct fields' do
     expected_fields = [:id, :title, :project, :author,
                        :file_name, :content, :description,
-                       :visibility, :created_at, :updated_at,
+                       :visibility_level, :created_at, :updated_at,
                        :web_url, :raw_url, :notes, :discussions,
                        :user_permissions, :description_html]
 

spec/requests/api/graphql/mutations/snippets/create_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'Creating a Snippet' do
+  include GraphqlHelpers
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project) { create(:project) }
+  let(:content) { 'Initial content' }
+  let(:description) { 'Initial description' }
+  let(:title) { 'Initial title' }
+  let(:file_name) { 'Initial file_name' }
+  let(:visibility_level) { 'public' }
+  let(:project_path) { nil }
+
+  let(:mutation) do
+    variables = {
+      content: content,
+      description: description,
+      visibility_level: visibility_level,
+      file_name: file_name,
+      title: title,
+      project_path: project_path
+    }
+
+    graphql_mutation(:create_snippet, variables)
+  end
+
+  def mutation_response
+    graphql_mutation_response(:create_snippet)
+  end
+
+  context 'when the user does not have permission' do
+    let(:current_user) { nil }
+
+    it_behaves_like 'a mutation that returns top-level errors',
+                    errors: [Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR]
+
+    it 'does not create the Snippet' do
+      expect do
+        post_graphql_mutation(mutation, current_user: current_user)
+      end.not_to change { Snippet.count }
+    end
+
+    context 'when user is not authorized in the project' do
+      let(:project_path) { project.full_path }
+
+      it 'does not create the snippet when the user is not authorized' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.not_to change { Snippet.count }
+      end
+    end
+  end
+
+  context 'when the user has permission' do
+    let(:current_user) { user }
+
+    context 'with PersonalSnippet' do
+      it 'creates the Snippet' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.to change { Snippet.count }.by(1)
+      end
+
+      it 'returns the created Snippet' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response['snippet']['content']).to eq(content)
+        expect(mutation_response['snippet']['title']).to eq(title)
+        expect(mutation_response['snippet']['description']).to eq(description)
+        expect(mutation_response['snippet']['fileName']).to eq(file_name)
+        expect(mutation_response['snippet']['visibilityLevel']).to eq(visibility_level)
+        expect(mutation_response['snippet']['project']).to be_nil
+      end
+    end
+
+    context 'with ProjectSnippet' do
+      let(:project_path) { project.full_path }
+
+      before do
+        project.add_developer(current_user)
+      end
+
+      it 'creates the Snippet' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.to change { Snippet.count }.by(1)
+      end
+
+      it 'returns the created Snippet' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response['snippet']['content']).to eq(content)
+        expect(mutation_response['snippet']['title']).to eq(title)
+        expect(mutation_response['snippet']['description']).to eq(description)
+        expect(mutation_response['snippet']['fileName']).to eq(file_name)
+        expect(mutation_response['snippet']['visibilityLevel']).to eq(visibility_level)
+        expect(mutation_response['snippet']['project']['fullPath']).to eq(project_path)
+      end
+
+      context 'when the project path is invalid' do
+        let(:project_path) { 'foobar' }
+
+        it 'returns an an error' do
+          post_graphql_mutation(mutation, current_user: current_user)
+          errors = json_response['errors']
+
+          expect(errors.first['message']).to eq(Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR)
+        end
+      end
+
+      context 'when the feature is disabled' do
+        it 'returns an an error' do
+          project.project_feature.update_attribute(:snippets_access_level, ProjectFeature::DISABLED)
+
+          post_graphql_mutation(mutation, current_user: current_user)
+          errors = json_response['errors']
+
+          expect(errors.first['message']).to eq(Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR)
+        end
+      end
+    end
+
+    context 'when there are ActiveRecord validation errors' do
+      let(:title) { '' }
+
+      it_behaves_like 'a mutation that returns errors in the response', errors: ["Title can't be blank"]
+
+      it 'does not create the Snippet' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.not_to change { Snippet.count }
+      end
+
+      it 'does not return Snippet' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response['snippet']).to be_nil
+      end
+    end
+  end
+end

spec/requests/api/graphql/mutations/snippets/destroy_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'Destroying a Snippet' do
+  include GraphqlHelpers
+
+  let(:current_user) { snippet.author }
+  let(:mutation) do
+    variables = {
+      id: snippet.to_global_id.to_s
+    }
+
+    graphql_mutation(:destroy_snippet, variables)
+  end
+
+  def mutation_response
+    graphql_mutation_response(:destroy_snippet)
+  end
+
+  shared_examples 'graphql delete actions' do
+    context 'when the user does not have permission' do
+      let(:current_user) { create(:user) }
+
+      it_behaves_like 'a mutation that returns top-level errors',
+                      errors: [Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR]
+
+      it 'does not destroy the Snippet' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.not_to change { Snippet.count }
+      end
+    end
+
+    context 'when the user has permission' do
+      it 'destroys the Snippet' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.to change { Snippet.count }.by(-1)
+      end
+
+      it 'returns an empty Snippet' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response).to have_key('snippet')
+        expect(mutation_response['snippet']).to be_nil
+      end
+    end
+  end
+
+  describe 'PersonalSnippet' do
+    it_behaves_like 'graphql delete actions' do
+      let_it_be(:snippet) { create(:personal_snippet) }
+    end
+  end
+
+  describe 'ProjectSnippet' do
+    let_it_be(:project) { create(:project, :private) }
+    let_it_be(:snippet) { create(:project_snippet, :private, project: project, author: create(:user)) }
+
+    context 'when the author is not a member of the project' do
+      it 'returns an an error' do
+        post_graphql_mutation(mutation, current_user: current_user)
+        errors = json_response['errors']
+
+        expect(errors.first['message']).to eq(Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR)
+      end
+    end
+
+    context 'when the author is a member of the project' do
+      before do
+        project.add_developer(current_user)
+      end
+
+      it_behaves_like 'graphql delete actions'
+
+      context 'when the snippet project feature is disabled' do
+        it 'returns an an error' do
+          project.project_feature.update_attribute(:snippets_access_level, ProjectFeature::DISABLED)
+
+          post_graphql_mutation(mutation, current_user: current_user)
+          errors = json_response['errors']
+
+          expect(errors.first['message']).to eq(Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR)
+        end
+      end
+    end
+  end
+end

spec/requests/api/graphql/mutations/snippets/update_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'Updating a Snippet' do
+  include GraphqlHelpers
+
+  let_it_be(:original_content) { 'Initial content' }
+  let_it_be(:original_description) { 'Initial description' }
+  let_it_be(:original_title) { 'Initial title' }
+  let_it_be(:original_file_name) { 'Initial file_name' }
+  let(:updated_content) { 'Updated content' }
+  let(:updated_description) { 'Updated description' }
+  let(:updated_title) { 'Updated_title' }
+  let(:updated_file_name) { 'Updated file_name' }
+  let(:current_user) { snippet.author }
+
+  let(:mutation) do
+    variables = {
+      id: GitlabSchema.id_from_object(snippet).to_s,
+      content: updated_content,
+      description: updated_description,
+      visibility_level: 'public',
+      file_name: updated_file_name,
+      title: updated_title
+    }
+
+    graphql_mutation(:update_snippet, variables)
+  end
+
+  def mutation_response
+    graphql_mutation_response(:update_snippet)
+  end
+
+  shared_examples 'graphql update actions' do
+    context 'when the user does not have permission' do
+      let(:current_user) { create(:user) }
+
+      it_behaves_like 'a mutation that returns top-level errors',
+                      errors: [Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR]
+
+      it 'does not update the Snippet' do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.not_to change { snippet.reload }
+      end
+    end
+
+    context 'when the user has permission' do
+      it 'updates the Snippet' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(snippet.reload.title).to eq(updated_title)
+      end
+
+      it 'returns the updated Snippet' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response['snippet']['content']).to eq(updated_content)
+        expect(mutation_response['snippet']['title']).to eq(updated_title)
+        expect(mutation_response['snippet']['description']).to eq(updated_description)
+        expect(mutation_response['snippet']['fileName']).to eq(updated_file_name)
+        expect(mutation_response['snippet']['visibilityLevel']).to eq('public')
+      end
+
+      context 'when there are ActiveRecord validation errors' do
+        let(:updated_title) { '' }
+
+        it_behaves_like 'a mutation that returns errors in the response', errors: ["Title can't be blank"]
+
+        it 'does not update the Snippet' do
+          post_graphql_mutation(mutation, current_user: current_user)
+
+          expect(snippet.reload.title).to eq(original_title)
+        end
+
+        it 'returns the Snippet with its original values' do
+          post_graphql_mutation(mutation, current_user: current_user)
+
+          expect(mutation_response['snippet']['content']).to eq(original_content)
+          expect(mutation_response['snippet']['title']).to eq(original_title)
+          expect(mutation_response['snippet']['description']).to eq(original_description)
+          expect(mutation_response['snippet']['fileName']).to eq(original_file_name)
+          expect(mutation_response['snippet']['visibilityLevel']).to eq('private')
+        end
+      end
+    end
+  end
+
+  describe 'PersonalSnippet' do
+    it_behaves_like 'graphql update actions' do
+      let_it_be(:snippet) do
+        create(:personal_snippet,
+               :private,
+               file_name: original_file_name,
+               title: original_title,
+               content: original_content,
+               description: original_description)
+      end
+    end
+  end
+
+  describe 'ProjectSnippet' do
+    let_it_be(:project) { create(:project, :private) }
+    let_it_be(:snippet) do
+      create(:project_snippet,
+             :private,
+             project: project,
+             author: create(:user),
+             file_name: original_file_name,
+             title: original_title,
+             content: original_content,
+             description: original_description)
+    end
+
+    context 'when the author is not a member of the project' do
+      it 'returns an an error' do
+        post_graphql_mutation(mutation, current_user: current_user)
+        errors = json_response['errors']
+
+        expect(errors.first['message']).to eq(Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR)
+      end
+    end
+
+    context 'when the author is a member of the project' do
+      before do
+        project.add_developer(current_user)
+      end
+
+      it_behaves_like 'graphql update actions'
+
+      context 'when the snippet project feature is disabled' do
+        it 'returns an an error' do
+          project.project_feature.update_attribute(:snippets_access_level, ProjectFeature::DISABLED)
+
+          post_graphql_mutation(mutation, current_user: current_user)
+          errors = json_response['errors']
+
+          expect(errors.first['message']).to eq(Gitlab::Graphql::Authorize::AuthorizeResource::RESOURCE_ACCESS_ERROR)
+        end
+      end
+    end
+  end
+end