feat: support deleting a manifest from a remote registry

[yuehaoliang]

Resolve #473

Signed-off-by: Haoliang Yue yuehaoliang@microsoft.com

[codecov-commenter]

Codecov Report

Merging #506 (0937ff2) into main (551aca4) will increase coverage by 0.96%.
The diff coverage is 100.00%.

❗ Current head 0937ff2 differs from pull request most recent head e6e930b. Consider uploading reports for the commit e6e930b to get more accurate results

@@            Coverage Diff             @@
##             main     #506      +/-   ##
==========================================
+ Coverage   71.37%   72.33%   +0.96%     
==========================================
  Files          12       13       +1     
  Lines         489      506      +17     
==========================================
+ Hits          349      366      +17     
  Misses        112      112              
  Partials       28       28              

Impacted Files	Coverage Δ
cmd/oras/internal/option/confirmation.go	100.00% <100.00%> (ø)

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[shizhMSFT]

Suggest having io.Writer passed in for better unit tests.

Suggested change

	func (opts *Confirmation) AskForConfirmation(message string) (bool, error) {
	func (opts *Confirmation) AskForConfirmation(w io.Writer, prompt string) (bool, error) {

[yuehaoliang]

Suggest having io.Writer passed in for better unit tests.

I found a different approach to test a func with fmt.Scanln() in its body. Details are shown below, not sure which way makes more sense.

[shizhMSFT]

Try fmt.Fscanln

[yuehaoliang]

I wrote in this way because in the unit test, I can easily override the scanln() func.

var scanln func(a ...any) (n int, err error) = fmt.Scanln
func AskForConfirmation() {
	var response string
	scanln(&response)
}

Then, in the unit test, I can do things like.

TestConfirmation_AskForConfirmation(t *testing.T) {
	reset := func(input string) {
		scanln = func(a ...any) (n int, err error) {
			*a[0].(*string) = input
			return len([]byte(input)), nil
		}
	}
	reset("yes")
	// test for user input "yes"
	reset("no")
	// test for user input "no"
}

Compare to introducing w io.Writer to the func, it is a different way that I found to handle fmt.Scanln(). I think it's good, does it make sense to you? @shizhMSFT

[shizhMSFT]

The way of doing var scanln is too hacky. Since it is just for unit test, it does not worth it.

[yuehaoliang]

The way of doing var scanln is too hacky. Since it is just for unit test, it does not worth it.

No problem, will change to use w io.Writer and fmt.Fscanln().

[shizhMSFT]

Question: Can we delete multiple manifests at the same time?

[shizhMSFT]

/cc @FeynmanZhou

[shizhMSFT]

@yuehaoliang-microsoft Please create an issue for this question, and only address it in another PR after being well discussed.

[yuehaoliang]

@yuehaoliang-microsoft Please create an issue for this question, and only address it in another PR after being well discussed.

Created issue #560 to follow up deleting multiple manifest in a single command.

[shizhMSFT]

LGTM

[shizhMSFT]

LGTM