In softloud/neet: Coding to code::proof

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.path = "man/figures/README-",
  out.width = "50%",
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)

thoughts on using it so far

Still not convinced of the utlity of this code. Perhaps better simply to write an expect success as a neet. Trying it out, however, has been very useful for adopting some level of test-driven development.
One particular drawback of this code is that it messes up the error line when reporting, and that's a massive drag when debugging. However, I learnt a lot from building it.

neet:: Test for non-empty thing of expected type

A neet test tests for non-empty thing of expected type. This is what is referred to as a boundary condition test in RStudio's primers (todo: citation).

These expectations are intended to integrate into minimal testing workflow for development of data analyses. When developing a function, we will need parameters, and structure of the pipeline. These tests enable the developer to feel reassured the pipeline's functions are outputting non-empty thing of expected type, while the developer decides the best structure for an analysis pipeline.

A character string will be checked for being of string-length > 1.

A numeric is checked for not being NA, NULL, Inf, or -Inf.

A `list`` is checked for being of length > 1.

A data.frame is checked for having at least one row.

Installation

You can install the released version of neet from GitHub with:

# install devtools
install.packages(devtools) 

# use devtools to install package from github
devtools::install_github("softloud/neet")

Example

library(testthat)
library(neet)

## basic example code

# assertions check inputs of code in function scripts
assert_neet(3, "numeric") # test numeric
assert_neet("cat", "character") # test character string
assert_neet(mtcars, "data.frame") # test data frame

# tests to check neet expectations in testthat files
test_neet(3, "numeric") # test numeric
test_neet("cat", "character") # test character string
test_neet(mtcars, "data.frame") # test data frame

Workflow

The neet:: package supports a coding workflow.

workflow(0)

This section describes the test-driven workflow presented above as a code::proofed coding to doneness.

The model workflow comprises three stages, repeated three times, before returning to the start, the code::registration. We use model to suggest the workflow may be adapted for different use-cases.

Each phase consists of:

1. code::registration
2. tests
3. code

coding to code::proof workflow

The tests vary each time in complexity, so that the complete model cycle consists of ten phases of work:

1. code::registration

workflow(1)

In an issue on GitHub:

1. Describe the algorithm's intended purpose.
2. Describe the input parameters and how they will be tested.
3. Describe the output parameters and how they will be tested.

purpose

A duck that "quack"s.

input

Nothing.

output

• [ ] one neet
• [ ] all neets
• [ ] and the rest

Character string "quack".

1. neet tests, one per function

workflow(2)

Write a test to check the duck quacks at all. This test currently fails, because I have not written the code to make it pass, yet.

test_that(expect_match(duck(), "quack"))

1. code

workflow(3)

Write code to make the test pass.

# write function
duck <- function() {"quack!"}

And now no error message is returned.

test_that(expect_match(duck(), "quack"))

1. code::registration

Either update or rewrite the code::registration. It becomes more obvious what code needs to be written once the developer has spent some time again with the function.

• [x] one neet
• [ ] all neets

• [ ] and the rest

• neet tests, for all inputs for each function

workflow(5)

Now consider all inputs. Since we have nothing, we might consider the case where there is something, and write a test that expects an error.

test_that("function fails with input", {
  expect_error(duck(3))
})

1. code

The duck quacks sufficiently. No more code required!

1. code::registration

workflow(7)

Either update or rewrite the code::registration.

• [x] one neet
• [x] all neets

• [ ] and the rest

• tests, and the rest, i.e., any other cases to test for

I am satisified with the test coverage.

1. code

The duck quacks sufficiently.

1. code::registration

workflow(10)

• [x] one neet
• [x] all neets
• [x] and the rest

For the final code::registration, update the document for your future self with details you may need when implementing new features.

softloud/neet documentation built on May 31, 2020, 12:40 a.m.