Add test for Gitlab::Graphql::Docs::Renderer

spec/lib/gitlab/graphql/docs/renderer_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Graphql::Docs::Renderer do
+  describe '#contents' do
+    # Returns a Schema that uses the given `type`
+    def mock_schema(type)
+      query_type = Class.new(GraphQL::Schema::Object) do
+        graphql_name 'QueryType'
+
+        field :foo, type, null: true
+      end
+
+      GraphQL::Schema.define(query: query_type)
+    end
+
+    let_it_be(:template) { Rails.root.join('lib/gitlab/graphql/docs/templates/', 'default.md.haml') }
+
+    subject(:contents) do
+      described_class.new(
+        mock_schema(type).graphql_definition,
+        output_dir: nil,
+        template: template
+      ).contents
+    end
+
+    context 'A type with a field with a [Array] return type' do
+      let(:type) do
+        Class.new(GraphQL::Schema::Object) do
+          graphql_name 'ArrayTest'
+
+          field :foo, [GraphQL::STRING_TYPE], null: false, description: 'A description'
+        end
+      end
+
+      specify do
+        expectation = <<~DOC
+          ## ArrayTest
+
+          | Name  | Type  | Description |
+          | ---   |  ---- | ----------  |
+          | `foo` | String! => Array | A description |
+        DOC
+
+        is_expected.to include(expectation)
+      end
+    end
+
+    context 'A type with fields defined in reverse alphabetical order' do
+      let(:type) do
+        Class.new(GraphQL::Schema::Object) do
+          graphql_name 'OrderingTest'
+
+          field :foo, GraphQL::STRING_TYPE, null: false, description: 'A description of foo field'
+          field :bar, GraphQL::STRING_TYPE, null: false, description: 'A description of bar field'
+        end
+      end
+
+      specify do
+        expectation = <<~DOC
+          ## OrderingTest
+
+          | Name  | Type  | Description |
+          | ---   |  ---- | ----------  |
+          | `bar` | String! | A description of bar field |
+          | `foo` | String! | A description of foo field |
+        DOC
+
+        is_expected.to include(expectation)
+      end
+    end
+
+    context 'A type with a deprecated field' do
+      let(:type) do
+        Class.new(GraphQL::Schema::Object) do
+          graphql_name 'DeprecatedTest'
+
+          field :foo, GraphQL::STRING_TYPE, null: false, deprecation_reason: 'This is deprecated', description: 'A description'
+        end
+      end
+
+      specify do
+        expectation = <<~DOC
+          ## DeprecatedTest
+
+          | Name  | Type  | Description |
+          | ---   |  ---- | ----------  |
+          | `foo` **{warning-solid}** | String! | **Deprecated:** This is deprecated |
+        DOC
+
+        is_expected.to include(expectation)
+      end
+    end
+  end
+end