diff --git a/Gemfile.lock b/Gemfile.lock
index d0f7222..7f294a8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    annotato (0.2.3)
+    annotato (0.2.4)
       rails (>= 6.0)
 
 GEM
diff --git a/lib/annotato/enum_formatter.rb b/lib/annotato/enum_formatter.rb
index da915d5..2bc0ff1 100644
--- a/lib/annotato/enum_formatter.rb
+++ b/lib/annotato/enum_formatter.rb
@@ -8,19 +8,18 @@ module Annotato
   class EnumFormatter
     def self.format(conn, columns)
       # Collect columns backed by a native PG enum type.
-      # A native enum type is one that exists in pg_type with typtype = 'e'.
       enum_columns = columns.select { |col| pg_enum_type?(conn, col.sql_type) }
       return [] if enum_columns.empty?
 
-      enum_columns.map do |col|
+      enum_columns.flat_map do |col|
         labels = pg_enum_labels(conn, col.sql_type)
         lines = ["#  #{col.name} (#{col.sql_type}): ["]
-        lines += labels.map.with_index { |label, i|
+        labels.each_with_index do |label, i|
           comma = i == labels.size - 1 ? "" : ","
-          "#    #{label}#{comma}"
-        }
+          lines << "#    #{label}#{comma}"
+        end
         lines << "#  ]"
-        lines.join("\n")
+        lines
       end
     end
 
@@ -40,7 +39,7 @@ def self.format(conn, columns)
       conn.exec_query(
         "SELECT e.enumlabel FROM pg_enum e " \
         "JOIN pg_type t ON e.enumtypid = t.oid " \
-        "WHERE t.typname = $1 " \
+        "WHERE t.typname = $1 AND t.typtype = 'e' " \
         "ORDER BY e.enumsortorder",
         "SQL",
         [type_name]
diff --git a/lib/annotato/version.rb b/lib/annotato/version.rb
index 5ec7b83..f39ea3d 100644
--- a/lib/annotato/version.rb
+++ b/lib/annotato/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Annotato
-  VERSION = "0.2.3"
+  VERSION = "0.2.4"
 end
diff --git a/spec/annotato/enum_formatter_spec.rb b/spec/annotato/enum_formatter_spec.rb
index f12bd42..0b2f868 100644
--- a/spec/annotato/enum_formatter_spec.rb
+++ b/spec/annotato/enum_formatter_spec.rb
@@ -6,10 +6,6 @@
 RSpec.describe Annotato::EnumFormatter do
   let(:connection) { double("Connection") }
 
-  def pg_type_result(exists)
-    exists ? [{ "typname" => "my_enum" }] : []
-  end
-
   context "when no columns have a native PG enum type" do
     let(:columns) do
       [
@@ -38,17 +34,14 @@ def pg_type_result(exists)
     end
 
     before do
-      # bigint is not an enum
       allow(connection).to receive(:exec_query)
         .with(/SELECT 1 FROM pg_type/, anything, ["bigint"])
         .and_return([])
 
-      # access_link_category is a native enum
       allow(connection).to receive(:exec_query)
         .with(/SELECT 1 FROM pg_type/, anything, ["access_link_category"])
         .and_return([{ "typname" => "access_link_category" }])
 
-      # labels query
       allow(connection).to receive(:exec_query)
         .with(/SELECT e.enumlabel/, anything, ["access_link_category"])
         .and_return([
@@ -58,16 +51,21 @@ def pg_type_result(exists)
         ])
     end
 
-    it "formats the DB enum type definition" do
+    it "returns a flat array of comment lines" do
+      result = described_class.format(connection, columns)
+      expect(result).to eq([
+        "#  category (access_link_category): [",
+        "#    internal,",
+        "#    external,",
+        "#    partner",
+        "#  ]"
+      ])
+    end
+
+    it "includes all labels including the last one" do
       result = described_class.format(connection, columns)
-      expect(result.size).to eq(1)
-      expect(result.first).to eq(<<~ENUM.strip)
-        #  category (access_link_category): [
-        #    internal,
-        #    external,
-        #    partner
-        #  ]
-      ENUM
+      expect(result).to include("#    partner")
+      expect(result.last).to eq("#  ]")
     end
   end
 
@@ -91,10 +89,10 @@ def pg_type_result(exists)
 
     it "strips the array suffix and formats the enum type" do
       result = described_class.format(connection, columns)
-      expect(result.size).to eq(1)
-      expect(result.first).to include("roles (user_role[]): [")
-      expect(result.first).to include("#    admin,")
-      expect(result.first).to include("#    viewer")
+      expect(result).to include("#  roles (user_role[]): [")
+      expect(result).to include("#    admin,")
+      expect(result).to include("#    viewer")
+      expect(result).to include("#  ]")
     end
   end
 end