3 files changed, 60 insertions, 9 deletions
diff --git a/spec/graphql/resolvers/base_resolver_spec.rb b/spec/graphql/resolvers/base_resolver_spec.rb
new file mode 100644
index 00000000000..e3a34762b62
--- /dev/null
+++ b/spec/graphql/resolvers/base_resolver_spec.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Resolvers::BaseResolver do
+  include GraphqlHelpers
+
+  let(:resolver) do
+    Class.new(described_class) do
+      def resolve(**args)
+        [args, args]
+      end
+    end
+  end
+
+  describe '.single' do
+    it 'returns a subclass from the resolver' do
+      expect(resolver.single.superclass).to eq(resolver)
+    end
+
+    it 'returns the same subclass every time' do
+      expect(resolver.single.object_id).to eq(resolver.single.object_id)
+    end
+
+    it 'returns a resolver that gives the first result from the original resolver' do
+      result = resolve(resolver.single, args: { test: 1 })
+
+      expect(result).to eq(test: 1)
+    end
+  end
+end
diff --git a/spec/graphql/resolvers/issues_resolver_spec.rb b/spec/graphql/resolvers/issues_resolver_spec.rb
index 1a54ab540fc..66de372e9fe 100644
--- a/spec/graphql/resolvers/issues_resolver_spec.rb
+++ b/spec/graphql/resolvers/issues_resolver_spec.rb
@@ -33,6 +33,10 @@ describe Resolvers::IssuesResolver do
       expect(resolve_issues).to contain_exactly(issue, issue2)
     end
 
+    it 'finds a specific issue with iid' do
+      expect(resolve_issues(iid: issue.iid)).to contain_exactly(issue)
+    end
+
     it 'finds a specific issue with iids' do
       expect(resolve_issues(iids: issue.iid)).to contain_exactly(issue)
     end
diff --git a/spec/graphql/resolvers/merge_request_resolver_spec.rb b/spec/graphql/resolvers/merge_requests_resolver_spec.rb
index 73993b3a039..ab3c426b2cd 100644
--- a/spec/graphql/resolvers/merge_request_resolver_spec.rb
+++ b/spec/graphql/resolvers/merge_requests_resolver_spec.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe Resolvers::MergeRequestResolver do
+describe Resolvers::MergeRequestsResolver do
   include GraphqlHelpers
 
   set(:project) { create(:project, :repository) }
@@ -16,9 +16,17 @@ describe Resolvers::MergeRequestResolver do
   let(:other_iid) { other_merge_request.iid }
 
   describe '#resolve' do
-    it 'batch-resolves merge requests by target project full path and IID' do
+    it 'batch-resolves by target project full path and individual IID' do
       result = batch(max_queries: 2) do
-        [resolve_mr(project, iid_1), resolve_mr(project, iid_2)]
+        resolve_mr(project, iid: iid_1) + resolve_mr(project, iid: iid_2)
+      end
+
+      expect(result).to contain_exactly(merge_request_1, merge_request_2)
+    end
+
+    it 'batch-resolves by target project full path and IIDS' do
+      result = batch(max_queries: 2) do
+        resolve_mr(project, iids: [iid_1, iid_2])
       end
 
       expect(result).to contain_exactly(merge_request_1, merge_request_2)
@@ -26,20 +34,28 @@ describe Resolvers::MergeRequestResolver do
 
     it 'can batch-resolve merge requests from different projects' do
       result = batch(max_queries: 3) do
-        [resolve_mr(project, iid_1), resolve_mr(project, iid_2), resolve_mr(other_project, other_iid)]
+        resolve_mr(project, iid: iid_1) +
+          resolve_mr(project, iid: iid_2) +
+          resolve_mr(other_project, iid: other_iid)
       end
 
       expect(result).to contain_exactly(merge_request_1, merge_request_2, other_merge_request)
     end
 
-    it 'resolves an unknown iid to nil' do
-      result = batch { resolve_mr(project, -1) }
+    it 'resolves an unknown iid to be empty' do
+      result = batch { resolve_mr(project, iid: -1) }
+
+      expect(result).to be_empty
+    end
+
+    it 'resolves empty iids to be empty' do
+      result = batch { resolve_mr(project, iids: []) }
 
-      expect(result).to be_nil
+      expect(result).to be_empty
     end
   end
 
-  def resolve_mr(project, iid)
-    resolve(described_class, obj: project, args: { iid: iid })
+  def resolve_mr(project, args)
+    resolve(described_class, obj: project, args: args)
   end
 end