1 files changed, 41 insertions, 0 deletions
diff --git a/spec/lib/gitlab/database/postgres_foreign_key_spec.rb b/spec/lib/gitlab/database/postgres_foreign_key_spec.rb
new file mode 100644
index 00000000000..ec39e5bfee7
--- /dev/null
+++ b/spec/lib/gitlab/database/postgres_foreign_key_spec.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Database::PostgresForeignKey, type: :model do
+  # PostgresForeignKey does not `behaves_like 'a postgres model'` because it does not correspond 1-1 with a single entry
+  # in pg_class
+
+  before do
+    ActiveRecord::Base.connection.execute(<<~SQL)
+    CREATE TABLE public.referenced_table (
+      id bigserial primary key not null
+    );
+
+    CREATE TABLE public.other_referenced_table (
+      id bigserial primary key not null
+    );
+
+    CREATE TABLE public.constrained_table (
+      id bigserial primary key not null,
+      referenced_table_id bigint not null,
+      other_referenced_table_id bigint not null,
+      CONSTRAINT fk_constrained_to_referenced FOREIGN KEY(referenced_table_id) REFERENCES referenced_table(id),
+      CONSTRAINT fk_constrained_to_other_referenced FOREIGN KEY(other_referenced_table_id)
+         REFERENCES other_referenced_table(id)
+    );
+    SQL
+  end
+
+  describe '#by_referenced_table_identifier' do
+    it 'throws an error when the identifier name is not fully qualified' do
+      expect { described_class.by_referenced_table_identifier('referenced_table') }.to raise_error(ArgumentError, /not fully qualified/)
+    end
+
+    it 'finds the foreign keys for the referenced table' do
+      expected = described_class.find_by!(name: 'fk_constrained_to_referenced')
+
+      expect(described_class.by_referenced_table_identifier('public.referenced_table')).to contain_exactly(expected)
+    end
+  end
+end