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#110 - Fix Slice bug producing a \n when provided with an empty slice #115

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#110 - Fix Slice bug producing a \n when provided with an empty slice #115

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04c4e92
Added if statement that returns no new line if there an empty splice
hsheikhali1 May 3, 2022
12bf171
add todo nnote
hsheikhali1 May 3, 2022
21d3ec1
added passing test
hsheikhali1P May 10, 2022
308cdc6
removed commented out string
hsheikhali1P May 10, 2022
195bc2f
removed tests for list files and moved them
hsheikhali1 May 10, 2022
7c6bf02
removed todo
hsheikhali1 May 10, 2022
ea4b50d
updated test to include an empty list
hsheikhali1 May 11, 2022
99fc5ae
removed log package ...
hsheikhali1 May 14, 2022
32cfe70
Merge remote-tracking branch 'origin' into hsheikhali/fix-slice-bug
hsheikhali1P Aug 26, 2022
1786a6d
added suggestions
hsheikhali1P Aug 26, 2022
b3566e4
fixing commit history
hsheikhali1 Aug 26, 2022
f6676bd
fixing commit history
hsheikhali1 Aug 26, 2022
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3 changes: 3 additions & 0 deletions script.go
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Original file line number Diff line number Diff line change
Expand Up @@ -291,6 +291,9 @@ func ListFiles(path string) *Pipe {
// Slice creates a pipe containing each element of the supplied slice of
// strings, one per line.
func Slice(s []string) *Pipe {
if len(s) <= 0 {
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@bitfield bitfield Jun 2, 2022

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It seems unlikely that len(s) could be less than zero, doesn't it?

Clearly the special case here is where the length equals zero, but it seems a shame to duplicate virtually the whole function for this case. Actually, the difference in behaviour is whether or not we add a final newline. It seems slightly neater to me to isolate just that in the special-case branch.

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@bitfield bitfield Jun 2, 2022

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And if s has zero elements, there's no need to call strings.Join in any case: there's nothing to join.

Instead, what about:

if len(s) == 0 {
	return NewPipe()
}
return Echo(strings.Join(s, "\n") + "\n")

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@hsheikhali1 hsheikhali1 Aug 26, 2022

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That's a very good point ! @bitfield thanks!

return Echo(strings.Join(s, ""))
}
return Echo(strings.Join(s, "\n") + "\n")
}

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15 changes: 15 additions & 0 deletions script_test.go
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Expand Up @@ -1120,6 +1120,21 @@ func TestSliceProducesElementsOfSpecifiedSliceOnePerLine(t *testing.T) {
}
}

func TestSliceProducesNoElementsWhenProvidedWithAnEmptyList(t *testing.T) {
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@bitfield bitfield Jun 2, 2022

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Actually, since the result of Slice is a Pipe, maybe we should say something like:

func TestSliceGivenEmptySliceProducesEmptyPipe

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@bitfield bitfield Jun 2, 2022

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And we could probably use an extra test here for the non-empty slice behaviour, couldn't we? (The fact that we don't have one is entirely on me, but this is a good chance to add it.)

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@hsheikhali1 hsheikhali1 Aug 26, 2022

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Doesn't this test cover non-empty slice behaviour ?

func TestSliceProducesElementsOfSpecifiedSliceOnePerLine(t *testing.T) {
	t.Parallel()
	want := "1\n2\n3\n"
	got, err := script.Slice([]string{"1", "2", "3"}).String()
	if err != nil {
		t.Fatal(err)
	}
	if !cmp.Equal(want, got) {
		t.Error(cmp.Diff(want, got))
	}
}

t.Parallel()

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@bitfield bitfield Jun 2, 2022

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This is great, but it's house style with this project to use no blank lines within functions. To my mind, they just make the function longer without providing any benefit.

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@hsheikhali1 hsheikhali1 Aug 26, 2022

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This is a thing I have built into muscle memory from my typescript work.. I noticed some Go devs prefer not to have a bunch of blank lines

want := ""
got, err := script.Slice([]string{}).String()

if err != nil {
t.Fatal(err)
}

if !cmp.Equal(want, got) {
t.Error(cmp.Diff(want, got))
}
}

func TestStdinReadsFromProgramStandardInput(t *testing.T) {
t.Parallel()
// dummy test to prove coverage
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