1 files changed, 49 insertions, 0 deletions
diff --git a/spec/db/schema_spec.rb b/spec/db/schema_spec.rb
new file mode 100644
index 000000000..a7fe0a162
--- /dev/null
+++ b/spec/db/schema_spec.rb
@@ -0,0 +1,49 @@
+RSpec.describe ActiveRecord::Schema do
+  it "uses type `bigint` for primary and foreign keys" do
+    expect('db/schema.rb').to use_bigint_keys
+  end
+end
+
+
+RSpec::Matchers.define :use_bigint_keys do
+  match do |filename|
+    @original = ""
+    @expected = ""
+
+    File.open(filename, 'r') do |f|
+      f.each_line do |line|
+        expected_line = line
+
+        # Primary key
+        if line =~ /create_table\s/ &&
+          !(line =~ /id: \s+ (?: :bigserial | false)/x)
+          expected_line = line.sub(/(create_table\s"\w+",\s)/, '\1id: :bigserial, ')
+        end
+
+        # Foreign key
+        if line =~ /t\.integer\s+"\w+_id"/ &&
+          !(line =~ /limit: 8/)
+          expected_line = line.sub(/(t.integer\s+"\w+")/, '\1, limit: 8')
+        end
+
+        @original += line
+        @expected += expected_line
+      end
+    end
+
+    @original == @expected
+  end
+
+  failure_message do |filename|
+    <<-EOS
+expected #{filename.inspect} to use bigint keys
+Diff: #{diff}
+    EOS
+  end
+
+  def diff
+    RSpec::Support::Differ.new(
+      color: RSpec::Matchers.configuration.color?
+    ).diff_as_string(@original, @expected)
+  end
+end