1 files changed, 37 insertions, 0 deletions
diff --git a/spec/lib/gitlab/database/pg_class_spec.rb b/spec/lib/gitlab/database/pg_class_spec.rb
new file mode 100644
index 00000000000..83b50415a6c
--- /dev/null
+++ b/spec/lib/gitlab/database/pg_class_spec.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Database::PgClass, type: :model do
+  describe '#cardinality_estimate' do
+    context 'when no information is available' do
+      subject { described_class.new(reltuples: 0.0).cardinality_estimate }
+
+      it 'returns nil for the estimate' do
+        expect(subject).to be_nil
+      end
+    end
+
+    context 'with reltuples available' do
+      subject { described_class.new(reltuples: 42.0).cardinality_estimate }
+
+      it 'returns the reltuples for the estimate' do
+        expect(subject).to eq(42)
+      end
+    end
+  end
+
+  describe '.for_table' do
+    let(:relname) { :projects }
+
+    subject { described_class.for_table(relname) }
+
+    it 'returns PgClass for this table' do
+      expect(subject).to be_a(described_class)
+    end
+
+    it 'matches the relname' do
+      expect(subject.relname).to eq(relname.to_s)
+    end
+  end
+end