laser

Preface

Like unit testing but dislike mocks and stubs? Want to keep your business logic separate from your side effects? In this blog post, I'll demonstrate a novel approach to testing which relies not on the [Dependency Injection][4] pattern, but an algebraic data structure and some simple functions.

A Real World Example

I was recently working on a system for a real estate company which merged a

laser

Inputs

Can we (today) vary these values at runtime?

• window_size_mib (const here)
• sector_size_gib (const here)
• !*wrapping_variant (?)
• drg_parents (const here)
• expander_parents (const here)
• graph_name (? - ignore)

laser

#!/usr/bin/env bash

expected_circle_config_sha256sum="2ea6a7c8f63088b107b6346685866629abdf165f0b457f8856880ea2dcfc63b1"

integration_branch=laser/test-integrations-$(date +%s)

go_filecoin_branch=master
go_filecoin_url=git@github.com:filecoin-project/go-filecoin.git

rust_fil_proofs_branch=master

laser

Housekeeping

General rules for making a distributed book club like this not-awful:

• keep your mic muted unless you're speaking
• raise your hand if you have something to say and wait for someone to call on you
• if you're raising your hand and nobody calls on you, type a message into the chat

Chapter 1

laser

public abstract class Tree {
  // Constructor private so the type is sealed.
  private Tree() {}

  public abstract <T> T match(Function<Empty, T> a,
                              Function<Leaf, T> b,
                              Function<Node, T> c);

  public static final class Empty extends Tree {
    public <T> T match(Function<Empty, T> a,

laser

echo ""
echo "$(date "+%T") 'fork' a process..."
# opens the file as input fd 666 before the background job (curl) is started
exec 666< <(curl -s 'http://www.fakeresponse.com/api/?sleep=4')

echo ""
echo "$(date "+%T") 'fork' second process..."
# opens the file as input fd 666 before the background job (curl) is started
exec 777< <(curl -s 'https://cdn.bringatrailer.com/wp-content/uploads/2017/09/59c4506ce4ca8_P6155050-e1506103879707.jpg')

laser

go test ./... \
  -v \
  -run "$(cat commands/foo_test.go \
    | grep -oE "^func Test[^(]*" \
    | sed -e "s/func //" \
    | tr "\n" "|" \
    | sed -e "s/|$//")"

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var codes = {
    "AD": "AD\\d{3}",
    "AM": "(37)?\\d{4}",
    "AR": "([A-HJ-NP-Z])?\\d{4}([A-Z]{3})?",
    "AS": "96799",
    "AT": "\\d{4}",
    "AU": "\\d{4}",
    "AX": "22\\d{3}",
    "AZ": "\\d{4}",
    "BA": "\\d{5}",

laser

Keybase proof

I hereby claim:

• I am laser on github.
• I am lasericus (https://keybase.io/lasericus) on keybase.
• I have a public key ASC9zkxig-oNF8OP2GS2jTNPEW0GOVoPMIfR0WvR0buulQo

To claim this, I am signing this object:

laser

DHT|peer-id
0|uPody
1|nGjie
2|ur5o2
3|mM69R
4|26R1S
5|jyzxZ
6|wtMS5
7|MDKez
8|t26G5