Update tag list conformance test to verify sort order

Makefile

@@ -92,7 +92,7 @@ conformance-test:
 
 conformance-binary: $(OUTPUT_DIRNAME)/conformance.test
 
-TEST_REGISTRY_CONTAINER ?= ghcr.io/project-zot/zot-minimal-linux-amd64:v2.0.0-rc6@sha256:bf95a94849cd9c6f596fb10e5a2d03b74267e7886d1ba0b3dab33337d9e46e5c
+TEST_REGISTRY_CONTAINER ?= ghcr.io/project-zot/zot-minimal-linux-amd64:v2.0.4@sha256:0312c23d9658b912a0d4db5c6ecd6d4391c1211912f10de3e9a52685f000318a
 registry-ci:
 	docker rm -f oci-conformance && \
 		mkdir -p $(OUTPUT_DIRNAME) && \

conformance/03_discovery_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -61,17 +62,18 @@ var test03ContentDiscovery = func() {
 				SkipIfDisabled(contentDiscovery)
 				RunOnlyIf(runContentDiscoverySetup)
 				for i := 0; i < numTags; i++ {
-					tag := fmt.Sprintf("test%d", i)
-					tagList = append(tagList, tag)
-					req := client.NewRequest(reggie.PUT, "/v2/<name>/manifests/<reference>",
-						reggie.WithReference(tag)).
-						SetHeader("Content-Type", "application/vnd.oci.image.manifest.v1+json").
-						SetBody(manifests[2].Content)
-					resp, err := client.Do(req)
-					Expect(err).To(BeNil())
-					Expect(resp.StatusCode()).To(SatisfyAll(
-						BeNumerically(">=", 200),
-						BeNumerically("<", 300)))
+					for _, tag := range []string{"test" + strconv.Itoa(i), "TEST" + strconv.Itoa(i)} {
+						tagList = append(tagList, tag)
+						req := client.NewRequest(reggie.PUT, "/v2/<name>/manifests/<reference>",
+							reggie.WithReference(tag)).
+							SetHeader("Content-Type", "application/vnd.oci.image.manifest.v1+json").
+							SetBody(manifests[2].Content)
+						resp, err := client.Do(req)
+						Expect(err).To(BeNil())
+						Expect(resp.StatusCode()).To(SatisfyAll(
+							BeNumerically(">=", 200),
+							BeNumerically("<", 300)))
+					}
 				}
 				req := client.NewRequest(reggie.GET, "/v2/<name>/tags/list")
 				resp, err := client.Do(req)
@@ -253,14 +255,23 @@ var test03ContentDiscovery = func() {
 		})
 
 		g.Context("Test content discovery endpoints (listing tags)", func() {
-			g.Specify("GET request to list tags should yield 200 response", func() {
+			g.Specify("GET request to list tags should yield 200 response and be in sorted order", func() {
 				SkipIfDisabled(contentDiscovery)
 				req := client.NewRequest(reggie.GET, "/v2/<name>/tags/list")
 				resp, err := client.Do(req)
 				Expect(err).To(BeNil())
 				Expect(resp.StatusCode()).To(Equal(http.StatusOK))
 				tagList = getTagList(resp)
 				numTags = len(tagList)
+				// If the list is not empty, the tags MUST be in lexical order (i.e. case-insensitive alphanumeric order).
+				sortedTagListLexical := append([]string{}, tagList...)
+				sort.SliceStable(sortedTagListLexical, func(i, j int) bool {
+					return strings.ToLower(sortedTagListLexical[i]) < strings.ToLower(sortedTagListLexical[j])
+				})
+				// Historically, registries have not been lexical, so allow `sort.Strings` to be valid too.
+				sortedTagListAsciibetical := append([]string{}, tagList...)
+				sort.Strings(sortedTagListAsciibetical)
+				Expect(tagList).To(Or(Equal(sortedTagListLexical), Equal(sortedTagListAsciibetical)))
 			})
 
 			g.Specify("GET number of tags should be limitable by `n` query parameter", func() {

spec.md

@@ -520,7 +520,7 @@ To fetch the list of tags, perform a `GET` request to a path in the following fo
 `<name>` is the namespace of the repository.
 Assuming a repository is found, this request MUST return a `200 OK` response code.
 The list of tags MAY be empty if there are no tags on the repository.
-If the list is not empty, the tags MUST be in lexical order (i.e. case-insensitive alphanumeric order).
+If the list is not empty, the tags MUST be in lexical (i.e. case-insensitive alphanumeric order) or "ASCIIbetical" ([Go's `sort.Strings`](https://pkg.go.dev/sort#Strings)) order.
 
 Upon success, the response MUST be a json body in the following format:
 ```json
@@ -546,7 +546,7 @@ A `Link` header MAY be included in the response when additional tags are availab
 If included, the `Link` header MUST be set according to [RFC5988](https://www.rfc-editor.org/rfc/rfc5988.html) with the Relation Type `rel="next"`.
 When `n` is zero, this endpoint MUST return an empty list, and MUST NOT include a `Link` header.
 Without the `last` query parameter (described next), the list returned will start at the beginning of the list and include `<int>` results.
-As above, the tags MUST be in lexical order.
+As above, the tags MUST be in lexical or "ASCIIbetical" order.
 
 The `last` query parameter provides further means for limiting the number of tags.
 It is usually used in combination with the `n` parameter: `/v2/<name>/tags/list?n=<int>&last=<tagname>` <sup>[end-8b](#endpoints)</sup>
@@ -555,7 +555,7 @@ It is usually used in combination with the `n` parameter: `/v2/<name>/tags/list?
 `<tagname>` MUST NOT be a numerical index, but rather it MUST be a proper tag.
 A request of this sort will return up to `<int>` tags, beginning non-inclusively with `<tagname>`.
 That is to say, `<tagname>` will not be included in the results, but up to `<int>` tags *after* `<tagname>` will be returned.
-The tags MUST be in lexical order.
+The tags MUST be in lexical or "ASCIIbetical" order.
 
 When using the `last` query parameter, the `n` parameter is OPTIONAL.