Merge branch '13495-c-design-at-version-types' into 'master'

13495-c: Add design-at-version GraphQL entities

See merge request gitlab-org/gitlab!21276

.gitignore

@@ -86,4 +86,4 @@ jsdoc/
 .projections.json
 /qa/.rakeTasks
 webpack-dev-server.json
-.nvimrc
+/.nvimrc

app/graphql/gitlab_schema.rb

@@ -57,20 +57,24 @@ class GitlabSchema < GraphQL::Schema
       object.to_global_id
     end
 
+    # Find an object by looking it up from its global ID, passed as a string.
+    #
+    # This is the composition of 'parse_gid' and 'find_by_gid', see these
+    # methods for further documentation.
     def object_from_id(global_id, ctx = {})
-      expected_type = ctx[:expected_type]
-      gid = GlobalID.parse(global_id)
+      gid = parse_gid(global_id, ctx)
 
-      unless gid
-        raise Gitlab::Graphql::Errors::ArgumentError, "#{global_id} is not a valid GitLab id."
-      end
-
-      if expected_type && !gid.model_class.ancestors.include?(expected_type)
-        vars = { global_id: global_id, expected_type: expected_type }
-        msg = _('%{global_id} is not a valid id for %{expected_type}.') % vars
-        raise Gitlab::Graphql::Errors::ArgumentError, msg
+      find_by_gid(gid)
     end
 
+    # Find an object by looking it up from its 'GlobalID'.
+    #
+    # * For `ApplicationRecord`s, this is equivalent to
+    #   `global_id.model_class.find(gid.model_id)`, but more efficient.
+    # * For classes that implement `.lazy_find(global_id)`, this class method
+    #   will be called.
+    # * All other classes will use `GlobalID#find`
+    def find_by_gid(gid)
       if gid.model_class < ApplicationRecord
         Gitlab::Graphql::Loaders::BatchModelLoader.new(gid.model_class, gid.model_id).find
       elsif gid.model_class.respond_to?(:lazy_find)
@@ -80,6 +84,38 @@ class GitlabSchema < GraphQL::Schema
       end
     end
 
+    # Parse a string to a GlobalID, raising ArgumentError if there are problems
+    # with it.
+    #
+    # Problems that may occur:
+    #  * it may not be syntactically valid
+    #  * it may not match the expected type (see below)
+    #
+    # Options:
+    #  * :expected_type [Class] - the type of object this GlobalID should refer to.
+    #
+    # e.g.
+    #
+    # ```
+    #   gid = GitlabSchema.parse_gid(my_string, expected_type: ::Project)
+    #   project_id = gid.model_id
+    #   gid.model_class == ::Project
+    # ```
+    def parse_gid(global_id, ctx = {})
+      expected_type = ctx[:expected_type]
+      gid = GlobalID.parse(global_id)
+
+      raise Gitlab::Graphql::Errors::ArgumentError, "#{global_id} is not a valid GitLab id." unless gid
+
+      if expected_type && !gid.model_class.ancestors.include?(expected_type)
+        vars = { global_id: global_id, expected_type: expected_type }
+        msg = _('%{global_id} is not a valid id for %{expected_type}.') % vars
+        raise Gitlab::Graphql::Errors::ArgumentError, msg
+      end
+
+      gid
+    end
+
     private
 
     def max_query_complexity(ctx)

doc/api/graphql/reference/gitlab_schema.graphql

@@ -529,9 +529,9 @@ type CreateSnippetPayload {
   snippet: Snippet
 }
 
-type Design implements Noteable {
+type Design implements DesignFields & Noteable {
   """
-  Diff refs of the design
+  The diff refs for this design
   """
   diffRefs: DiffRefs!
 
@@ -561,33 +561,32 @@ type Design implements Noteable {
   ): DiscussionConnection!
 
   """
-  Type of change made to the design at the version specified by the `atVersion`
-  argument if supplied. Defaults to the latest version
+  How this design was changed in the current version
   """
   event: DesignVersionEvent!
 
   """
-  Filename of the design file
+  The filename of the design
   """
   filename: String!
 
   """
-  Full path of the design file
+  The full path to the design file
   """
   fullPath: String!
 
   """
-  ID of the design
+  The ID of this design
   """
   id: ID!
 
   """
-  Image of the design
+  The URL of the image
   """
   image: String!
 
   """
-  Issue associated with the design
+  The issue the design belongs to
   """
   issue: Issue!
 
@@ -617,17 +616,17 @@ type Design implements Noteable {
   ): NoteConnection!
 
   """
-  Total count of user-created notes for the design
+  The total count of user-created notes for this design
   """
   notesCount: Int!
 
   """
-  Project associated with the design
+  The project the design belongs to
   """
   project: Project!
 
   """
-  All versions related to the design, ordered newest first
+  All versions related to this design ordered newest first
   """
   versions(
     """
@@ -765,6 +764,53 @@ type DesignEdge {
   node: Design
 }
 
+interface DesignFields {
+  """
+  The diff refs for this design
+  """
+  diffRefs: DiffRefs!
+
+  """
+  How this design was changed in the current version
+  """
+  event: DesignVersionEvent!
+
+  """
+  The filename of the design
+  """
+  filename: String!
+
+  """
+  The full path to the design file
+  """
+  fullPath: String!
+
+  """
+  The ID of this design
+  """
+  id: ID!
+
+  """
+  The URL of the image
+  """
+  image: String!
+
+  """
+  The issue the design belongs to
+  """
+  issue: Issue!
+
+  """
+  The total count of user-created notes for this design
+  """
+  notesCount: Int!
+
+  """
+  The project the design belongs to
+  """
+  project: Project!
+}
+
 """
 Autogenerated input type of DesignManagementDelete
 """

doc/api/graphql/reference/gitlab_schema.json

@@ -10350,7 +10350,7 @@
           "fields": [
             {
               "name": "diffRefs",
-              "description": "Diff refs of the design",
+              "description": "The diff refs for this design",
               "args": [
 
               ],
@@ -10425,7 +10425,7 @@
             },
             {
               "name": "event",
-              "description": "Type of change made to the design at the version specified by the `atVersion` argument if supplied. Defaults to the latest version",
+              "description": "How this design was changed in the current version",
               "args": [
 
               ],
@@ -10443,7 +10443,7 @@
             },
             {
               "name": "filename",
-              "description": "Filename of the design file",
+              "description": "The filename of the design",
               "args": [
 
               ],
@@ -10461,7 +10461,7 @@
             },
             {
               "name": "fullPath",
-              "description": "Full path of the design file",
+              "description": "The full path to the design file",
               "args": [
 
               ],
@@ -10479,7 +10479,7 @@
             },
             {
               "name": "id",
-              "description": "ID of the design",
+              "description": "The ID of this design",
               "args": [
 
               ],
@@ -10497,7 +10497,7 @@
             },
             {
               "name": "image",
-              "description": "Image of the design",
+              "description": "The URL of the image",
               "args": [
 
               ],
@@ -10515,7 +10515,7 @@
             },
             {
               "name": "issue",
-              "description": "Issue associated with the design",
+              "description": "The issue the design belongs to",
               "args": [
 
               ],
@@ -10590,7 +10590,7 @@
             },
             {
               "name": "notesCount",
-              "description": "Total count of user-created notes for the design",
+              "description": "The total count of user-created notes for this design",
               "args": [
 
               ],
@@ -10608,7 +10608,7 @@
             },
             {
               "name": "project",
-              "description": "Project associated with the design",
+              "description": "The project the design belongs to",
               "args": [
 
               ],
@@ -10626,7 +10626,7 @@
             },
             {
               "name": "versions",
-              "description": "All versions related to the design, ordered newest first",
+              "description": "All versions related to this design ordered newest first",
               "args": [
                 {
                   "name": "after",
@@ -10688,11 +10688,195 @@
               "kind": "INTERFACE",
               "name": "Noteable",
               "ofType": null
+            },
+            {
+              "kind": "INTERFACE",
+              "name": "DesignFields",
+              "ofType": null
             }
           ],
           "enumValues": null,
           "possibleTypes": null
         },
+        {
+          "kind": "INTERFACE",
+          "name": "DesignFields",
+          "description": null,
+          "fields": [
+            {
+              "name": "diffRefs",
+              "description": "The diff refs for this design",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "OBJECT",
+                  "name": "DiffRefs",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "event",
+              "description": "How this design was changed in the current version",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "ENUM",
+                  "name": "DesignVersionEvent",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "filename",
+              "description": "The filename of the design",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "String",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "fullPath",
+              "description": "The full path to the design file",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "String",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "id",
+              "description": "The ID of this design",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "ID",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "image",
+              "description": "The URL of the image",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "String",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "issue",
+              "description": "The issue the design belongs to",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "OBJECT",
+                  "name": "Issue",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "notesCount",
+              "description": "The total count of user-created notes for this design",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "Int",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "project",
+              "description": "The project the design belongs to",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "OBJECT",
+                  "name": "Project",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            }
+          ],
+          "inputFields": null,
+          "interfaces": null,
+          "enumValues": null,
+          "possibleTypes": [
+            {
+              "kind": "OBJECT",
+              "name": "Design",
+              "ofType": null
+            }
+          ]
+        },
         {
           "kind": "ENUM",
           "name": "DesignVersionEvent",

doc/api/graphql/reference/index.md

@@ -104,15 +104,15 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 
 | Name  | Type  | Description |
 | ---   |  ---- | ----------  |
-| `id` | ID! | ID of the design |
-| `project` | Project! | Project associated with the design |
-| `issue` | Issue! | Issue associated with the design |
-| `notesCount` | Int! | Total count of user-created notes for the design |
-| `filename` | String! | Filename of the design file |
-| `fullPath` | String! | Full path of the design file |
-| `event` | DesignVersionEvent! | Type of change made to the design at the version specified by the `atVersion` argument if supplied. Defaults to the latest version |
-| `image` | String! | Image of the design |
-| `diffRefs` | DiffRefs! | Diff refs of the design |
+| `id` | ID! | The ID of this design |
+| `project` | Project! | The project the design belongs to |
+| `issue` | Issue! | The issue the design belongs to |
+| `filename` | String! | The filename of the design |
+| `fullPath` | String! | The full path to the design file |
+| `image` | String! | The URL of the image |
+| `diffRefs` | DiffRefs! | The diff refs for this design |
+| `event` | DesignVersionEvent! | How this design was changed in the current version |
+| `notesCount` | Int! | The total count of user-created notes for this design |
 
 ### DesignCollection
 

ee/app/graphql/types/design_management/design_at_version_type.rb

+# frozen_string_literal: true
+
+module Types
+  module DesignManagement
+    class DesignAtVersionType < BaseObject
+      graphql_name 'DesignAtVersion'
+
+      description 'A design pinned to a specific version'
+
+      authorize :read_design
+
+      delegate :design, :version, to: :object
+      delegate :issue, :filename, :full_path, :diff_refs, to: :design
+
+      implements ::Types::DesignManagement::DesignFields
+
+      field :version,
+            Types::DesignManagement::VersionType,
+            null: false,
+            description: 'The version this design-at-versions is pinned to'
+
+      field :design,
+            Types::DesignManagement::DesignType,
+            null: false,
+            description: 'The underlying design.'
+
+      def cached_stateful_version(_parent)
+        version
+      end
+
+      def notes_count
+        design.user_notes_count
+      end
+    end
+  end
+end

ee/app/graphql/types/design_management/design_fields.rb

+# frozen_string_literal: true
+
+module Types
+  module DesignManagement
+    module DesignFields
+      include BaseInterface
+
+      field_class Types::BaseField
+
+      field :id, GraphQL::ID_TYPE, description: 'The ID of this design', null: false
+      field :project, Types::ProjectType, null: false, description: 'The project the design belongs to'
+      field :issue, Types::IssueType, null: false, description: 'The issue the design belongs to'
+      field :filename, GraphQL::STRING_TYPE, null: false, description: 'The filename of the design'
+      field :full_path, GraphQL::STRING_TYPE, null: false, description: 'The full path to the design file'
+      field :image, GraphQL::STRING_TYPE, null: false, extras: [:parent], description: 'The URL of the image'
+      field :diff_refs, Types::DiffRefsType,
+            null: false,
+            calls_gitaly: true,
+            extras: [:parent],
+            description: 'The diff refs for this design'
+      field :event, Types::DesignManagement::DesignVersionEventEnum,
+            null: false,
+            extras: [:parent],
+            description: 'How this design was changed in the current version'
+      field :notes_count,
+            GraphQL::INT_TYPE,
+            null: false,
+            method: :user_notes_count,
+            description: 'The total count of user-created notes for this design'
+
+      def diff_refs(parent:)
+        version = cached_stateful_version(parent)
+        version.diff_refs
+      end
+
+      def image(parent:)
+        sha = cached_stateful_version(parent).sha
+
+        ::Gitlab::Routing.url_helpers.project_design_url(design.project, design, sha)
+      end
+
+      def event(parent:)
+        version = cached_stateful_version(parent)
+
+        action = cached_actions_for_version(version)[design.id]
+
+        action&.event || ::Types::DesignManagement::DesignVersionEventEnum::NONE
+      end
+
+      def cached_actions_for_version(version)
+        Gitlab::SafeRequestStore.fetch(['DesignFields', 'actions_for_version', version.id]) do
+          version.actions.to_h { |dv| [dv.design_id, dv] }
+        end
+      end
+
+      def project
+        ::Gitlab::Graphql::Loaders::BatchModelLoader.new(::Project, design.project_id).find
+      end
+
+      def issue
+        ::Gitlab::Graphql::Loaders::BatchModelLoader.new(::Issue, design.issue_id).find
+      end
+    end
+  end
+end

ee/app/graphql/types/design_management/design_type.rb

@@ -7,53 +7,17 @@ module Types
 
       authorize :read_design
 
-      implements(Types::Notes::NoteableType)
-
       alias_method :design, :object
 
-      field :id, GraphQL::ID_TYPE, null: false,
-            description: 'ID of the design'
-      field :project, Types::ProjectType, null: false,
-            description: 'Project associated with the design'
-      field :issue, Types::IssueType, null: false,
-            description: 'Issue associated with the design'
-      field :notes_count, GraphQL::INT_TYPE, null: false,
-            method: :user_notes_count,
-            description: 'Total count of user-created notes for the design'
-      field :filename, GraphQL::STRING_TYPE, null: false,
-            description: 'Filename of the design file'
-      field :full_path, GraphQL::STRING_TYPE, null: false,
-            description: 'Full path of the design file'
-      field :event, Types::DesignManagement::DesignVersionEventEnum, null: false,
-            description: 'Type of change made to the design at the version specified by the `atVersion` argument '\
-                         'if supplied. Defaults to the latest version',
-            extras: [:parent]
-      field :image, GraphQL::STRING_TYPE, null: false,
-            description: 'Image of the design',
-            extras: [:parent]
-      field :diff_refs, Types::DiffRefsType, null: false,
-            description: 'Diff refs of the design',
-            calls_gitaly: true
+      implements(Types::Notes::NoteableType)
+      implements(Types::DesignManagement::DesignFields)
+
       field :versions,
             Types::DesignManagement::VersionType.connection_type,
             resolver: Resolvers::DesignManagement::VersionResolver,
-            description: 'All versions related to the design, ordered newest first',
+            description: "All versions related to this design ordered newest first",
             extras: [:parent]
 
-      def image(parent:)
-        sha = cached_stateful_version(parent).sha
-
-        Gitlab::Routing.url_helpers.project_design_url(design.project, design, sha)
-      end
-
-      def event(parent:)
-        version = cached_stateful_version(parent)
-
-        action = cached_actions_for_version(version)[design.id]
-
-        action&.event || Types::DesignManagement::DesignVersionEventEnum::NONE
-      end
-
       # Returns a `DesignManagement::Version` for this query based on the
       # `atVersion` argument passed to a parent node if present, or otherwise
       # the most recent `Version` for the issue.
@@ -71,12 +35,6 @@ module Types
         end
       end
 
-      def cached_actions_for_version(version)
-        Gitlab::SafeRequestStore.fetch([request_cache_base_key, 'actions_for_version', version.id]) do
-          version.actions.to_h { |dv| [dv.design_id, dv] }
-        end
-      end
-
       def request_cache_base_key
         self.class.name
       end

ee/app/models/design_management/design_at_version.rb

@@ -34,6 +34,14 @@ module DesignManagement
       "#{design.id}.#{version.id}"
     end
 
+    def ==(other)
+      return false unless other && self.class == other.class
+
+      other.id == id
+    end
+
+    alias_method :eql?, :==
+
     def self.lazy_find(id)
       BatchLoader.for(id).batch do |ids, callback|
         find(ids).each do |record|

ee/spec/graphql/types/design_management/design_at_version_type_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+# describe GitlabSchema.types['DesignAtVersion'] do
+# This not available on the schema until we mount it somewhere
+describe ::Types::DesignManagement::DesignAtVersionType.to_graphql do
+  it_behaves_like 'a GraphQL type with design fields' do
+    let(:extra_design_fields) { %i[version design] }
+    let_it_be(:design) { create(:design, :with_versions) }
+    let(:object_id) do
+      version = design.versions.first
+      GitlabSchema.id_from_object(create(:design_at_version, design: design, version: version))
+    end
+    let_it_be(:object_id_b) { GitlabSchema.id_from_object(create(:design_at_version)) }
+    let(:object_type) { ::Types::DesignManagement::DesignAtVersionType }
+  end
+end

ee/spec/graphql/types/design_management/design_type_spec.rb

@@ -3,26 +3,11 @@
 require 'spec_helper'
 
 describe GitlabSchema.types['Design'] do
-  it { expect(described_class).to require_graphql_authorizations(:read_design) }
-
-  it { expect(described_class.interfaces).to include(Types::Notes::NoteableType.to_graphql) }
-
-  it 'exposes the expected fields' do
-    expected_fields = %i[
-      diff_refs
-      discussions
-      event
-      filename
-      full_path
-      id
-      image
-      issue
-      notes
-      notes_count
-      project
-      versions
-    ]
-
-    is_expected.to have_graphql_fields(*expected_fields)
+  it_behaves_like 'a GraphQL type with design fields' do
+    let(:extra_design_fields) { %i[notes discussions versions] }
+    let_it_be(:design) { create(:design, :with_versions) }
+    let(:object_id) { GitlabSchema.id_from_object(design) }
+    let_it_be(:object_id_b) { GitlabSchema.id_from_object(create(:design, :with_versions)) }
+    let(:object_type) { ::Types::DesignManagement::DesignType }
   end
 end

ee/spec/models/design_management/design_at_version_spec.rb

@@ -18,6 +18,59 @@ describe DesignManagement::DesignAtVersion do
     end
   end
 
+  describe '#==' do
+    it 'identifies objects created with the same parameters as equal' do
+      design = build_stubbed(:design, issue: issue)
+      version = build_stubbed(:design_version, designs: [design], issue: issue)
+
+      this = build_stubbed(:design_at_version, design: design, version: version)
+      other = build_stubbed(:design_at_version, design: design, version: version)
+
+      expect(this).to eq(other)
+      expect(other).to eq(this)
+    end
+
+    it 'identifies unequal objects as unequal, by virtue of their version' do
+      design = build_stubbed(:design, issue: issue)
+      version_a = build_stubbed(:design_version, designs: [design])
+      version_b = build_stubbed(:design_version, designs: [design])
+
+      this = build_stubbed(:design_at_version, design: design, version: version_a)
+      other = build_stubbed(:design_at_version, design: design, version: version_b)
+
+      expect(this).not_to eq(nil)
+      expect(this).not_to eq(design)
+      expect(this).not_to eq(other)
+      expect(other).not_to eq(this)
+    end
+
+    it 'identifies unequal objects as unequal, by virtue of their design' do
+      design_a = build_stubbed(:design, issue: issue)
+      design_b = build_stubbed(:design, issue: issue)
+      version = build_stubbed(:design_version, designs: [design_a, design_b])
+
+      this = build_stubbed(:design_at_version, design: design_a, version: version)
+      other = build_stubbed(:design_at_version, design: design_b, version: version)
+
+      expect(this).not_to eq(other)
+      expect(other).not_to eq(this)
+    end
+
+    it 'rejects objects with the same id and the wrong class' do
+      dav = build_stubbed(:design_at_version)
+
+      expect(dav).not_to eq(OpenStruct.new(id: dav.id))
+    end
+
+    it 'expects objects to be of the same type, not subtypes' do
+      subtype = Class.new(described_class)
+      dav = build_stubbed(:design_at_version)
+      other = subtype.new(design: dav.design, version: dav.version)
+
+      expect(dav).not_to eq(other)
+    end
+  end
+
   describe 'status methods' do
     let!(:design_a) { create(:design, issue: issue) }
     let!(:design_b) { create(:design, issue: issue) }

ee/spec/support/shared_examples/design_fields.rb

+# frozen_string_literal: true
+
+# To use these shared examples, you may define a value in scope named
+# `extra_design_fields`, to pass any extra fields in addition to the
+# standard design fields.
+shared_examples 'a GraphQL type with design fields' do
+  let(:extra_design_fields) { [] }
+
+  it { expect(described_class).to require_graphql_authorizations(:read_design) }
+
+  it 'exposes the expected design fields' do
+    expected_fields = %i[
+      id
+      project
+      issue
+      filename
+      full_path
+      image
+      diff_refs
+      event
+      notes_count
+    ] + extra_design_fields
+
+    is_expected.to have_graphql_fields(*expected_fields).only
+  end
+
+  describe '#image' do
+    let(:schema) { GitlabSchema }
+    let(:query) { GraphQL::Query.new(schema) }
+    let(:context) { double('Context', schema: schema, query: query, parent: nil) }
+    let(:field) { described_class.fields['image'] }
+    let(:args) { GraphQL::Query::Arguments::NO_ARGS }
+    let(:instance) do
+      object = GitlabSchema.sync_lazy(GitlabSchema.object_from_id(object_id))
+      object_type.authorized_new(object, query.context)
+    end
+    let(:instance_b) do
+      object_b = GitlabSchema.sync_lazy(GitlabSchema.object_from_id(object_id_b))
+      object_type.authorized_new(object_b, query.context)
+    end
+
+    it 'resolves to the design image URL' do
+      image = field.resolve(instance, args, context)
+      sha = design.versions.first.sha
+      url = ::Gitlab::Routing.url_helpers.project_design_url(design.project, design, sha)
+
+      expect(image).to eq(url)
+    end
+
+    it 'has better than O(N) peformance', :request_store do
+      # Assuming designs have been loaded (as they must be), the following
+      # queries are required:
+      # For each distinct version:
+      #  - design_management_versions
+      #    (Request store is needed so that each version is fetched only once.)
+      # For each distinct issue
+      #  - issues
+      # For each distinct project
+      #  - projects
+      #  - routes
+      #  - namespaces
+      # Here that total is:
+      #   - 2 x issues
+      #   - 2 x versions
+      #   - 2 x (projects + routes + namespaces)
+      #   = 10
+      expect(instance).not_to eq(instance_b) # preload designs themselves.
+      expect do
+        image_a = field.resolve(instance, args, context)
+        image_b = field.resolve(instance, args, context)
+        image_c = field.resolve(instance_b, args, context)
+        image_d = field.resolve(instance_b, args, context)
+        expect(image_a).to eq(image_b)
+        expect(image_c).not_to eq(image_b)
+        expect(image_c).to eq(image_d)
+      end.not_to exceed_query_limit(10)
+    end
+  end
+end

spec/graphql/gitlab_schema_spec.rb

@@ -124,14 +124,26 @@ describe GitlabSchema do
 
   describe '.object_from_id' do
     context 'for subclasses of `ApplicationRecord`' do
-      it 'returns the correct record' do
-        user = create(:user)
+      let_it_be(:user) { create(:user) }
 
+      it 'returns the correct record' do
         result = described_class.object_from_id(user.to_global_id.to_s)
 
         expect(result.sync).to eq(user)
       end
 
+      it 'returns the correct record, of the expected type' do
+        result = described_class.object_from_id(user.to_global_id.to_s, expected_type: ::User)
+
+        expect(result.sync).to eq(user)
+      end
+
+      it 'fails if the type does not match' do
+        expect do
+          described_class.object_from_id(user.to_global_id.to_s, expected_type: ::Project)
+        end.to raise_error(Gitlab::Graphql::Errors::ArgumentError)
+      end
+
       it 'batchloads the queries' do
         user1 = create(:user)
         user2 = create(:user)

spec/graphql/types/query_type_spec.rb

@@ -7,7 +7,16 @@ describe GitlabSchema.types['Query'] do
     expect(described_class.graphql_name).to eq('Query')
   end
 
-  it { is_expected.to have_graphql_fields(:project, :namespace, :group, :echo, :metadata, :current_user, :snippets) }
+  it do
+    is_expected.to have_graphql_fields(:project,
+                                       :namespace,
+                                       :group,
+                                       :echo,
+                                       :metadata,
+                                       :current_user,
+                                       :snippets
+                                      ).at_least
+  end
 
   describe 'namespace field' do
     subject { described_class.fields['namespace'] }

spec/support/helpers/graphql_helpers.rb

@@ -105,12 +105,15 @@ module GraphqlHelpers
   end
 
   def query_graphql_field(name, attributes = {}, fields = nil)
-    fields ||= all_graphql_fields_for(name.classify)
-    attributes = attributes_to_graphql(attributes)
-    attributes = "(#{attributes})" if attributes.present?
+    field_params = if attributes.present?
+                     "(#{attributes_to_graphql(attributes)})"
+                   else
+                     ''
+                   end
+
     <<~QUERY
-      #{name}#{attributes}
-      #{wrap_fields(fields)}
+      #{GraphqlHelpers.fieldnamerize(name.to_s)}#{field_params}
+      #{wrap_fields(fields || all_graphql_fields_for(name.to_s.classify))}
     QUERY
   end
 
@@ -301,6 +304,17 @@ module GraphqlHelpers
   def global_id_of(model)
     model.to_global_id.to_s
   end
+
+  def missing_required_argument(path, argument)
+    a_hash_including(
+      'path' => ['query'].concat(path),
+      'extensions' => a_hash_including('code' => 'missingRequiredArguments', 'arguments' => argument.to_s)
+    )
+  end
+
+  def custom_graphql_error(path, msg)
+    a_hash_including('path' => path, 'message' => msg)
+  end
 end
 
 # This warms our schema, doing this as part of loading the helpers to avoid

spec/support/matchers/graphql_matchers.rb

@@ -11,9 +11,23 @@ RSpec::Matchers.define :have_graphql_fields do |*expected|
     Array.wrap(expected).map { |name| GraphqlHelpers.fieldnamerize(name) }
   end
 
+  @allow_extra = false
+
+  chain :only do
+    @allow_extra = false
+  end
+
+  chain :at_least do
+    @allow_extra = true
+  end
+
   match do |kls|
+    if @allow_extra
+      expect(kls.fields.keys).to include(*expected_field_names)
+    else
       expect(kls.fields.keys).to contain_exactly(*expected_field_names)
     end
+  end
 
   failure_message do |kls|
     missing = expected_field_names - kls.fields.keys
@@ -22,7 +36,7 @@ RSpec::Matchers.define :have_graphql_fields do |*expected|
     message = []
 
     message << "is missing fields: <#{missing.inspect}>" if missing.any?
-    message << "contained unexpected fields: <#{extra.inspect}>" if extra.any?
+    message << "contained unexpected fields: <#{extra.inspect}>" if extra.any? && !@allow_extra
 
     message.join("\n")
   end

spec/support/shared_examples/graphql/failure_to_find_anything.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+# Shared example for legal queries that are expected to return nil.
+# Requires the following let bindings to be defined:
+#  - post_query: action to send the query
+#  - path: array of keys from query root to the result
+shared_examples 'a failure to find anything' do
+  it 'finds nothing' do
+    post_query
+
+    data = graphql_data.dig(*path)
+
+    expect(data).to be_nil
+  end
+end