nuget: handle RepositoryDetails without BaseAddress

nuget/lib/dependabot/nuget/update_checker/version_finder.rb

@@ -106,17 +106,16 @@ def available_v3_versions
             listing.
               fetch("versions", []).
               map do |v|
-                nuspec_url =
-                  listing.fetch("listing_details").
-                  fetch(:versions_url).
+                listing_details = listing.fetch("listing_details")
+                nuspec_url = listing_details.
+                             fetch(:versions_url, nil)&.
                   gsub(/index\.json$/, "#{v}/#{sanitized_name}.nuspec")
 
                 {
                   version: version_class.new(v),
                   nuspec_url: nuspec_url,
                   source_url: nil,
-                  repo_url:
-                    listing.fetch("listing_details").fetch(:repository_url)
+                  repo_url: listing_details.fetch(:repository_url)
                 }
               end
           end

nuget/spec/dependabot/nuget/update_checker/version_finder_spec.rb

@@ -309,6 +309,10 @@
       let(:custom_repo_url) do
         "https://www.myget.org/F/exceptionless/api/v3/index.json"
       end
+      let(:custom_nuget_search_url) do
+        "https://www.myget.org/F/exceptionless/api/v3/"\
+        "query?q=microsoft.extensions.dependencymodel&prerelease=true"
+      end
       before do
         stub_request(:get, nuget_versions_url).to_return(status: 404)
         stub_request(:get, nuget_search_url).to_return(status: 404)
@@ -323,9 +327,6 @@
         custom_nuget_versions_url =
           "https://www.myget.org/F/exceptionless/api/v3/flatcontainer/"\
           "microsoft.extensions.dependencymodel/index.json"
-        custom_nuget_search_url =
-          "https://www.myget.org/F/exceptionless/api/v3/"\
-          "query?q=microsoft.extensions.dependencymodel&prerelease=true"
         stub_request(:get, custom_nuget_versions_url).to_return(status: 404)
         stub_request(:get, custom_nuget_versions_url).
           with(basic_auth: %w(my passw0rd)).
@@ -337,6 +338,23 @@
       end
 
       its([:version]) { is_expected.to eq(version_class.new("2.1.0")) }
+
+      context "that does not return PackageBaseAddress" do
+        let(:custom_repo_url) { "http://localhost:8082/artifactory/api/nuget/v3/nuget-local" }
+        let(:custom_nuget_search_url) do
+          "http://localhost:8082/artifactory/api/nuget/v3/nuget-local/"\
+          "query?prerelease=true&q=microsoft.extensions.dependencymodel"
+        end
+        before do
+          stub_request(:get, custom_repo_url).
+            to_return(
+              status: 200,
+              body: fixture("nuget_responses", "artifactory_base.json")
+            )
+        end
+
+        its([:version]) { is_expected.to eq(version_class.new("2.1.0")) }
+      end
     end
 
     context "with a version range specified" do