Enable searching for MRs by updated_at

This adds `updated_before` and `updated_after` as arguments to
merge request resolvers.

This is already supported in the underlying finders, and in the REST
API.

Changelog: added

app/graphql/resolvers/merge_requests_resolver.rb

@@ -61,6 +61,12 @@ module Resolvers
     argument :created_before, Types::TimeType,
              required: false,
              description: 'Merge requests created before this timestamp.'
+    argument :updated_after, Types::TimeType,
+             required: false,
+             description: 'Merge requests updated after this timestamp.'
+    argument :updated_before, Types::TimeType,
+             required: false,
+             description: 'Merge requests updated before this timestamp.'
 
     argument :labels, [GraphQL::Types::String],
              required: false,

spec/graphql/types/project_type_spec.rb

@@ -300,6 +300,8 @@ RSpec.describe GitlabSchema.types['Project'] do
                                             :merged_before,
                                             :created_after,
                                             :created_before,
+                                            :updated_after,
+                                            :updated_before,
                                             :author_username,
                                             :assignee_username,
                                             :reviewer_username,

spec/requests/api/graphql/project/merge_requests_spec.rb

@@ -29,6 +29,10 @@ RSpec.describe 'getting merge request listings nested in a project' do
     create(:merge_request, :unique_branches, source_project: project)
   end
 
+  let(:all_merge_requests) do
+    [merge_request_a, merge_request_b, merge_request_c, merge_request_d, merge_request_e]
+  end
+
   let(:results) { graphql_data.dig('project', 'mergeRequests', 'nodes') }
 
   let(:search_params) { nil }
@@ -180,6 +184,39 @@ RSpec.describe 'getting merge request listings nested in a project' do
     it_behaves_like 'when searching with parameters'
   end
 
+  context 'when searching by update time' do
+    let(:start_time) { 10.days.ago }
+    let(:cutoff) { start_time + 36.hours }
+
+    before do
+      all_merge_requests.each_with_index do |mr, i|
+        mr.updated_at = start_time + i.days
+        mr.save!(touch: false)
+      end
+    end
+
+    context 'when searching by updated_after' do
+      let(:search_params) { { updated_after: cutoff } }
+      let(:mrs) { all_merge_requests[2..] }
+
+      it_behaves_like 'when searching with parameters'
+    end
+
+    context 'when searching by updated_before' do
+      let(:search_params) { { updated_before: cutoff } }
+      let(:mrs) { all_merge_requests[0..1] }
+
+      it_behaves_like 'when searching with parameters'
+    end
+
+    context 'when searching by updated_before and updated_after' do
+      let(:search_params) { { updated_after: cutoff, updated_before: cutoff + 2.days } }
+      let(:mrs) { all_merge_requests[2..3] }
+
+      it_behaves_like 'when searching with parameters'
+    end
+  end
+
   context 'when searching by combination' do
     let(:search_params) { { state: :closed, labels: [label.title] } }
     let(:mrs) { [merge_request_c] }

spec/support/graphql/arguments.rb

@@ -41,6 +41,7 @@ module Graphql
       when Hash then "{#{new(value)}}"
       when Integer, Float, Symbol then value.to_s
       when String then "\"#{value.gsub(/"/, '\\"')}\""
+      when Time, Date then "\"#{value.iso8601}\""
       when nil then 'null'
       when true then 'true'
       when false then 'false'