You can check a method is called or not by using receive in rspec.

describe "#method" do
  it "should call method_b" do
    @user = Persion.new
    expect(@user).to receive(:method_b)

    @user.method # method_b is called in method
  end
end
  • You should call receive before method_b is called
  • You can specify call count
expect(@user).to receive(:method_b).once
expect(@user).to receive(:method_b).twice