Skip to content

Commit

Permalink
Attempt to address issue quii#355 (quii#455)
Browse files Browse the repository at this point in the history 
* Fix markdown formatting in roman numerals

- Specified `console` language where not specified on fenced code blocks
that contain console output
- Switched `numeral_test.go` compilation error output from inline code
block to fenced code block since it is on a separate line
- Replaced indented code blocks in postscript section with fenced code
blocks set to `console`, retaining additional indentation
- Removed extraneous newlines and spaces

* Add missing allRomanNumerals data in section

This commit addresses quii#355 in which @twirrim notes that
`allRomanNumerals` wasn't defined in
<https://quii.gitbook.io/learn-go-with-tests/go-fundamentals/roman-numerals#write-enough-code-to-make-it-pass-7>
and was shown further down making it a bit confusing for readers. The
missing `allRomanNumerals` has now been added to ensure that readers
have the context they may need to show how `RomanNumerals` methods can
be called on `allRomanNumerals` since it is now of type `RomanNumerals`.

Fixes quii#355

Co-authored-by: Chris James <quii@hey.com>
  • Loading branch information
@lotia @quii
lotia and quii authored Apr 24, 2022
1 parent d9400fb commit 6cfedf1
Showing 1 changed file with 46 additions and 27 deletions.
73 changes: 46 additions & 27 deletions roman-numerals.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,9 @@ If you've got this far in the book this is hopefully feeling very boring and rou

## Try to run the test

`./numeral_test.go:6:9: undefined: ConvertToRoman`
```console
./numeral_test.go:6:9: undefined: ConvertToRoman
```

Let the compiler guide the way

Expand All @@ -53,7 +55,7 @@ func ConvertToRoman(arabic int) string {

It should run now

```
```console
=== RUN TestRomanNumerals
--- FAIL: TestRomanNumerals (0.00s)
numeral_test.go:10: got '', want 'I'
Expand Down Expand Up @@ -104,7 +106,7 @@ func TestRomanNumerals(t *testing.T) {

## Try to run the test

```
```console
=== RUN TestRomanNumerals/2_gets_converted_to_II
--- FAIL: TestRomanNumerals/2_gets_converted_to_II (0.00s)
numeral_test.go:20: got 'I', want 'II'
Expand Down Expand Up @@ -165,7 +167,7 @@ Add the following to our cases

## Try to run the test

```
```console
=== RUN TestRomanNumerals/3_gets_converted_to_III
--- FAIL: TestRomanNumerals/3_gets_converted_to_III (0.00s)
numeral_test.go:20: got 'I', want 'III'
Expand Down Expand Up @@ -220,8 +222,6 @@ Things start getting more complicated now. The Romans in their wisdom thought re

Instead you take the next highest symbol and then "subtract" by putting a symbol to the left of it. Not all symbols can be used as subtractors; only I (1), X (10) and C (100).



For example `5` in Roman Numerals is `V`. To create 4 you do not do `IIII`, instead you do `IV`.

## Write the test first
Expand All @@ -232,7 +232,7 @@ For example `5` in Roman Numerals is `V`. To create 4 you do not do `IIII`, inst

## Try to run the test

```
```console
=== RUN TestRomanNumerals/4_gets_converted_to_IV_(cant_repeat_more_than_3_times)
--- FAIL: TestRomanNumerals/4_gets_converted_to_IV_(cant_repeat_more_than_3_times) (0.00s)
numeral_test.go:24: got 'IIII', want 'IV'
Expand Down Expand Up @@ -290,7 +290,7 @@ Let's make 5 work

## Try to run the test

```
```console
=== RUN TestRomanNumerals/5_gets_converted_to_V
--- FAIL: TestRomanNumerals/5_gets_converted_to_V (0.00s)
numeral_test.go:25: got 'IIV', want 'V'
Expand Down Expand Up @@ -348,7 +348,6 @@ func ConvertToRoman(arabic int) string {

return result.String()
}

```

- Given the signals I'm reading from our code, driven from our tests of some very basic scenarios I can see that to build a Roman Numeral I need to subtract from `arabic` as I apply symbols
Expand All @@ -365,7 +364,7 @@ I'm pretty sure this approach will be valid for 6 (VI), 7 (VII) and 8 (VIII) too
```
## Try to run the test

```
```console
=== RUN TestRomanNumerals/9_gets_converted_to_IX
--- FAIL: TestRomanNumerals/9_gets_converted_to_IX (0.00s)
numeral_test.go:29: got 'VIV', want 'IX'
Expand Down Expand Up @@ -449,7 +448,6 @@ Here are some test cases, try and make them pass.

Need help? You can see what symbols to add in [this gist](https://gist.github.com/pamelafox/6c7b948213ba55332d86efd0f0b037de).


## And the rest!

Here are the remaining symbols
Expand Down Expand Up @@ -540,7 +538,6 @@ var allRomanNumerals = []RomanNumeral{

We're not done yet. Next we're going to write a function that converts _from_ a Roman Numeral to an `int`


## Write the test first

We can re-use our test cases here with a little refactoring
Expand All @@ -564,7 +561,7 @@ Notice I am using the slice functionality to just run one of the tests for now (

## Try to run the test

```
```console
./numeral_test.go:60:11: undefined: ConvertToArabic
```

Expand All @@ -580,7 +577,7 @@ func ConvertToArabic(roman string) int {

The test should now run and fail

```
```console
--- FAIL: TestConvertingToArabic (0.00s)
--- FAIL: TestConvertingToArabic/'I'_gets_converted_to_1 (0.00s)
numeral_test.go:62: got 0, want 1
Expand Down Expand Up @@ -642,6 +639,22 @@ func (r RomanNumerals) ValueOf(symbol string) int {
return 0
}

var allRomanNumerals = RomanNumerals{
{1000, "M"},
{900, "CM"},
{500, "D"},
{400, "CD"},
{100, "C"},
{90, "XC"},
{50, "L"},
{40, "XL"},
{10, "X"},
{9, "IX"},
{5, "V"},
{4, "IV"},
{1, "I"},
}

// later..
func ConvertToArabic(roman string) int {
total := 0
Expand Down Expand Up @@ -722,7 +735,7 @@ func couldBeSubtractive(index int, currentSymbol uint8, roman string) bool {

Let's move on to `cases[:5]`

```
```console
=== RUN TestConvertingToArabic/'V'_gets_converted_to_5
--- FAIL: TestConvertingToArabic/'V'_gets_converted_to_5 (0.00s)
numeral_test.go:62: got 1, want 5
Expand Down Expand Up @@ -805,7 +818,7 @@ It's still pretty nasty, but it's getting there.

If you start moving our `cases[:xx]` number through you'll see that quite a few are passing now. Remove the slice operator entirely and see which ones fail, here's some examples from my suite

```
```console
=== RUN TestConvertingToArabic/'XL'_gets_converted_to_40
--- FAIL: TestConvertingToArabic/'XL'_gets_converted_to_40 (0.00s)
numeral_test.go:62: got 60, want 40
Expand Down Expand Up @@ -990,7 +1003,7 @@ This feels like a good test to build us confidence because it should break if th

Our `assertion` function above takes a random number and runs our functions to test the property.

### Run our test
### Run our test

Try running it; your computer may hang for a while, so kill it when you're bored :)

Expand All @@ -1010,7 +1023,7 @@ assertion := func(arabic int) bool {

You should see something like this:

```
```console
=== RUN TestPropertiesOfConversion
2019/07/09 14:41:27 6849766357708982977
2019/07/09 14:41:27 -7028152357875163913
Expand Down Expand Up @@ -1103,14 +1116,18 @@ chapter so, in the interests of full disclosure, here's what he said.
> for 'finger', as we usually have ten of them. In the Arabic (also called
> Hindu-Arabic) number system there are ten of them. These Arabic digits are:
>
> 0 1 2 3 4 5 6 7 8 9
> ```console
> 0 1 2 3 4 5 6 7 8 9
> ```
>
> A _numeral_ is the representation of a number using a collection of digits.
> An Arabic numeral is a number represented by Arabic digits in a base 10
> positional number system. We say 'positional' because each digit has
> a different value based upon its position in the numeral. So
>
> 1337
> ```console
> 1337
> ```
>
> The `1` has a value of one thousand because its the first digit in a four
> digit numeral.
Expand All @@ -1123,11 +1140,13 @@ chapter so, in the interests of full disclosure, here's what he said.
> all tied to its representation - we can see this if we ask ourselves what the
> correct representation of this number is:
>
> 255
> 11111111
> two-hundred and fifty-five
> FF
> 377
> ```console
> 255
> 11111111
> two-hundred and fifty-five
> FF
> 377
> ```
>
> Yes, this is a trick question. They're all correct. They're the representation
> of the same number in the decimal, binary, English, hexadecimal and octal
Expand Down Expand Up @@ -1156,13 +1175,13 @@ chapter so, in the interests of full disclosure, here's what he said.
> sometimes `arabic` will be written as a decimal integer literal
>
> ```go
> ConvertToRoman(255)
> ConvertToRoman(255)
> ```
>
> But it could just as well be written
>
> ```go
> ConvertToRoman(0xFF)
> ConvertToRoman(0xFF)
> ```
>
> Really, we're not 'converting' from an Arabic numeral at all, we're 'printing' -
Expand Down

0 comments on commit 6cfedf1

Please sign in to comment.