spec.rb

      plaid_client_double = instance_double(Plaid::Client)
      plaid_transactions_double = instance_double(Plaid::Transactions)

      ENV["PLAID_ENVIRONMENT"] = "plaid_environment"
      ENV["PLAID_CLIENT_ID"] = "plaid_client_id"
      ENV["PLAID_SECRET"] = "plaid_secret"
      ENV["PLAID_CLIENT_NAME"] = "plaid_client_name"

      allow(Plaid::Client).to receive(:new).with(
        env: "plaid_environment",
        client_id: "plaid_client_id",
        secret: "plaid_secret",
      ).and_return(plaid_client_double)

      allow(plaid_client_double).to receive(:transactions)
        .and_return(plaid_transactions_double)