diff --git a/Gemfile b/Gemfile
index 4635044f..458900cb 100644
--- a/Gemfile
+++ b/Gemfile
@@ -20,7 +20,5 @@ gem "benchmark-driver", require: false
 gem "vernier", require: false, platform: :mri
 
 group :test do
-  gem "simplecov", "< 1.0.0", require: false, platforms: %i[mri windows]
-  gem "simplecov-html",   require: false, platforms: %i[mri windows]
-  gem "simplecov-json",   require: false, platforms: %i[mri windows]
+  gem "simplecov", ">= 1.0.0", require: false, platforms: %i[mri windows]
 end
diff --git a/test/lib/helper.rb b/test/lib/helper.rb
index 80e41e48..0977b2e8 100644
--- a/test/lib/helper.rb
+++ b/test/lib/helper.rb
@@ -3,12 +3,10 @@
 
   require "simplecov"
 
-  # Cannot use ".simplecov" file: simplecov-json triggers a circular require.
-  require "simplecov-json"
-  SimpleCov.formatters = SimpleCov::Formatter::MultiFormatter.new([
+  SimpleCov.formatters = [
     SimpleCov::Formatter::HTMLFormatter,
     SimpleCov::Formatter::JSONFormatter,
-  ])
+  ]
 
   SimpleCov.start do
     command_name "Net::IMAP tests"