Being Functional at the London .NET User Group

Yesterday I presented my talk Being Functional to the London .NET User Group. First of all: thanks to Dylan and Ian and whoever else was involved for organizing this event and inviting me, and to Skills Matter for making their fantastic CodeNode venue available to the group! I had a great time and I believe everybody else did, too :)

Feel free to get back to me if you have any questions or comments! Here’s the download of samples and slides I used during the talk.

In addition to that, I was asked about unit tests in F#. I dug out a piece of code I wrote in the past, that executes some tests for the SpeakerFS sample included in the download. This code uses Xunit to run the tests:

module SpeakersFS.ButterworthTests
open System
open SpeakersFS
open Xunit

let check (expected: float) (actual: float) =
  Assert.Equal(expected, Math.Round(actual, 2))

module FirstOrder =
  [<Fact>]
  let firstOrderCapacitance_100Hz_8Ohm() =
    check 198.75 (Butterworth.firstOrderCapacitance 100.0 8.0)
  [<Fact>]
  let firstOrderCapacitance_400Hz_8Ohm() =
    check 49.69 (Butterworth.firstOrderCapacitance 400.0 8.0)
  [<Fact>]
  let firstOrderCapacitance_2000Hz_8Ohm() =
    check 9.94 (Butterworth.firstOrderCapacitance 2000.0 8.0)
  [<Fact>]
  let firstOrderCapacitance_100Hz_4Ohm() =
    check 397.5 (Butterworth.firstOrderCapacitance 100.0 4.0)
  [<Fact>]
  let firstOrderCapacitance_400Hz_4Ohm() =
    check 99.38 (Butterworth.firstOrderCapacitance 400.0 4.0)
  [<Fact>]
  let firstOrderCapacitance_2000Hz_4Ohm() =
    check 19.88 (Butterworth.firstOrderCapacitance 2000.0 4.0)
  [<Fact>]
  let firstOrderInductance_100Hz_8Ohm() =
    check 12.74 (Butterworth.firstOrderInductance 100.0 8.0)
  [<Fact>]
  let firstOrderInductance_400Hz_8Ohm() =
    check 3.18 (Butterworth.firstOrderInductance 400.0 8.0)
  [<Fact>]
  let firstOrderInductance_2000Hz_8Ohm() =
    check 0.64 (Butterworth.firstOrderInductance 2000.0 8.0)
  [<Fact>]
  let firstOrderInductance_100Hz_4Ohm() =
    check 6.37 (Butterworth.firstOrderInductance 100.0 4.0)
  [<Fact>]
  let firstOrderInductance_400Hz_4Ohm() =
    check 1.59 (Butterworth.firstOrderInductance 400.0 4.0)
  [<Fact>]
  let firstOrderInductance_2000Hz_4Ohm() =
    check 0.32 (Butterworth.firstOrderInductance 2000.0 4.0)

module SecondOrder =
  [<Fact>]
  let secondOrderCapacitance_100Hz_8Ohm() =
    check 140.63 (Butterworth.secondOrderCapacitance 100.0 8.0)
  [<Fact>]
  let secondOrderCapacitance_400Hz_8Ohm() =
    check 35.16 (Butterworth.secondOrderCapacitance 400.0 8.0)
  [<Fact>]
  let secondOrderCapacitance_2000Hz_8Ohm() =
    check 7.03 (Butterworth.secondOrderCapacitance 2000.0 8.0)
  [<Fact>]
  let secondOrderCapacitance_100Hz_4Ohm() =
    check 281.25 (Butterworth.secondOrderCapacitance 100.0 4.0)
  [<Fact>]
  let secondOrderCapacitance_400Hz_4Ohm() =
    check 70.31 (Butterworth.secondOrderCapacitance 400.0 4.0)
  [<Fact>]
  let secondOrderCapacitance_2000Hz_4Ohm() =
    check 14.06 (Butterworth.secondOrderCapacitance 2000.0 4.0)
  [<Fact>]
  let secondOrderInductance_100Hz_8Ohm() =
    check 18.01 (Butterworth.secondOrderInductance 100.0 8.0)
  [<Fact>]
  let secondOrderInductance_400Hz_8Ohm() =
    check 4.50 (Butterworth.secondOrderInductance 400.0 8.0)
  [<Fact>]
  let secondOrderInductance_2000Hz_8Ohm() =
    check 0.90 (Butterworth.secondOrderInductance 2000.0 8.0)
  [<Fact>]
  let secondOrderInductance_100Hz_4Ohm() =
    check 9.00 (Butterworth.secondOrderInductance 100.0 4.0)
  [<Fact>]
  let secondOrderInductance_400Hz_4Ohm() =
    check 2.25 (Butterworth.secondOrderInductance 400.0 4.0)
  [<Fact>]
  let secondOrderInductance_2000Hz_4Ohm() =
    check 0.45 (Butterworth.secondOrderInductance 2000.0 4.0)