```ruby
$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
require 'bitcoin'

RSpec.configure do |config|
  config.before(:each) do |example|
    if example.metadata[:network]
      Bitcoin.chain_params = example.metadata[:network]
    else
      Bitcoin.chain_params = :testnet
    end
    if example.metadata[:use_secp256k1]
      ENV['SECP256K1_LIB_PATH'] = File.expand_path('lib/libsecp256k1.so', File.dirname(__FILE__))
    else
      ENV['SECP256K1_LIB_PATH'] = nil
    end
  end
end

def fixture_file(relative_path)
  file = File.read(File.join(File.dirname(__FILE__), 'fixtures', relative_path))
  JSON.parse(file)
end

module Bitcoin
  autoload :TestScriptParser, 'bitcoin/script/test_script_parser'
end```

Add secp256k1 library test for mac os
user
```ruby
$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
require 'bitcoin'

RSpec.configure do |config|
  config.before(:each) do |example|
    if example.metadata[:network]
      Bitcoin.chain_params = example.metadata[:network]
    else
      Bitcoin.chain_params = :testnet
    end
    if example.metadata[:use_secp256k1]
      host_os = RbConfig::CONFIG['host_os']
      case host_os
      when /darwin|mac os/
        ENV['SECP256K1_LIB_PATH'] = File.expand_path('lib/libsecp256k1.dylib', File.dirname(__FILE__))
      when /linux/
        ENV['SECP256K1_LIB_PATH'] = File.expand_path('lib/libsecp256k1.so', File.dirname(__FILE__))
      else
        raise "#{host_os} is an unsupported os."
      end
    else
      ENV['SECP256K1_LIB_PATH'] = nil
    end
  end
end

def fixture_file(relative_path)
  file = File.read(File.join(File.dirname(__FILE__), 'fixtures', relative_path))
  JSON.parse(file)
end

module Bitcoin
  autoload :TestScriptParser, 'bitcoin/script/test_script_parser'
end
```
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