1 files changed, 26 insertions, 7 deletions
diff --git a/spec/db/schema_spec.rb b/spec/db/schema_spec.rb
index 8111988ee..0e0fe780a 100644
--- a/spec/db/schema_spec.rb
+++ b/spec/db/schema_spec.rb
@@ -1,21 +1,40 @@
 RSpec.describe ActiveRecord::Schema do
   it "uses type `bigint` for primary and foreign keys" do
-    non_bigint_primary_keys = []
-    non_bigint_foreign_keys = []
+    expect('db/schema.rb').to use_bigint_keys
+  end
+end
+
+
+RSpec::Matchers.define :use_bigint_keys do
+  match do |filename|
+    @non_bigint_primary_keys = []
+    @non_bigint_foreign_keys = []
 
-    File.open('db/schema.rb', 'r') do |f|
-      non_bigint_primary_keys = f
+    File.open(filename, 'r') do |f|
+      @non_bigint_primary_keys = f
         .grep(/create_table /)
         .grep_v(/id: :bigserial/)
 
       f.rewind
 
-      non_bigint_foreign_keys = f
+      @non_bigint_foreign_keys = f
         .grep(/t\.integer +"\w+_id"/)
         .grep_v(/limit: 8/)
     end
 
-    expect(non_bigint_primary_keys).to be_empty
-    expect(non_bigint_foreign_keys).to be_empty
+    @non_bigint_primary_keys.empty? && @non_bigint_foreign_keys.empty?
+  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(@non_bigint_primary_keys + @non_bigint_foreign_keys, [])
   end
 end