Test renderReadmeFile (#23185)

Add test coverage to the important features of
[`routers.web.repo.renderReadmeFile`](https://github.com/go-gitea/gitea/blob/067b0c2664d127c552ccdfd264257caca4907a77/routers/web/repo/view.go#L273);
namely that:

- it can handle looking in docs/, .gitea/, and .github/
- it can handle choosing between multiple competing READMEs
- it prefers the localized README to the markdown README to the
plaintext README
- it can handle broken symlinks when processing all the options
- it uses the name of the symlink, not the name of the target of the
symlink

Author: kousu

models/db/iterate_test.go

@@ -25,7 +25,7 @@ func TestIterate(t *testing.T) {
 		return nil
 	})
 	assert.NoError(t, err)
-	assert.EqualValues(t, 83, repoCnt)
+	assert.EqualValues(t, 84, repoCnt)
 
 	err = db.Iterate(db.DefaultContext, nil, func(ctx context.Context, repoUnit *repo_model.RepoUnit) error {
 		reopUnit2 := repo_model.RepoUnit{ID: repoUnit.ID}

models/db/list_test.go

@@ -35,11 +35,11 @@ func TestFind(t *testing.T) {
 	var repoUnits []repo_model.RepoUnit
 	err := db.Find(db.DefaultContext, &opts, &repoUnits)
 	assert.NoError(t, err)
-	assert.EqualValues(t, 83, len(repoUnits))
+	assert.EqualValues(t, 84, len(repoUnits))
 
 	cnt, err := db.Count(db.DefaultContext, &opts, new(repo_model.RepoUnit))
 	assert.NoError(t, err)
-	assert.EqualValues(t, 83, cnt)
+	assert.EqualValues(t, 84, cnt)
 
 	repoUnits = make([]repo_model.RepoUnit, 0, 10)
 	newCnt, err := db.FindAndCount(db.DefaultContext, &opts, &repoUnits)

models/fixtures/repo_unit.yml

@@ -569,3 +569,9 @@
   type: 3
   config: "{\"IgnoreWhitespaceConflicts\":false,\"AllowMerge\":true,\"AllowRebase\":true,\"AllowRebaseMerge\":true,\"AllowSquash\":true}"
   created_unix: 946684810
+
+-
+  id: 84
+  repo_id: 56
+  type: 1
+  created_unix: 946684810

models/fixtures/repository.yml

@@ -1634,3 +1634,16 @@
   is_private: true
   num_issues: 1
   status: 0
+
+-
+  id: 56
+  owner_id: 2
+  owner_name: user2
+  lower_name: readme-test
+  name: readme-test
+  default_branch: master
+  is_empty: false
+  is_archived: false
+  is_private: true
+  status: 0
+  num_issues: 0

models/fixtures/user.yml

@@ -66,7 +66,7 @@
   num_followers: 2
   num_following: 1
   num_stars: 2
-  num_repos: 11
+  num_repos: 12
   num_teams: 0
   num_members: 0
   visibility: 0

tests/gitea-repositories-meta/user2/readme-test.git/HEAD

@@ -0,0 +1 @@
+ref: refs/heads/master

tests/gitea-repositories-meta/user2/readme-test.git/config

@@ -0,0 +1,4 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true

tests/gitea-repositories-meta/user2/readme-test.git/info/exclude

@@ -0,0 +1,6 @@
+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~

tests/gitea-repositories-meta/user2/readme-test.git/info/refs

@@ -0,0 +1,21 @@
+ea9ef877d1d88af76682d8798418081264f10cfc	refs/heads/fallbacks
+0d4c14db927c9ffba01fa7e126cc748b5c02c01e	refs/heads/fallbacks2
+c66d5b07c2063d3268707f22226c708b589574ef	refs/heads/fallbacks3
+89f8426e9eb5eff35c09b3565836c8f8e15d0ce9	refs/heads/fallbacks4
+b0e902496eae435ad03c92a5d479f916ef2d4893	refs/heads/fallbacks5
+84a5500b5cc040b11daf53fc42c542a99589dc76	refs/heads/fallbacks6
+cf406a96e416d7de5c4c1bbfffdd672300c822bf	refs/heads/fallbacks7
+0d6ac644b969e9199915a492da9dba08c179fd23	refs/heads/fallbacks8
+5038febc0c57215beb3748d7ae4091a25a4acc93	refs/heads/fallbacks9
+9134e1f178ca4cccf1a197142646f2d7627e8cd5	refs/heads/i18n
+744d2441e55bc0010d6b340d303f0106a627ad29	refs/heads/master
+3c492566170b057e962c025515ab38bbd7444077	refs/heads/plain
+3882d6373a0882a6739b3cd9b24d21c630621234	refs/heads/sp-ace
+bf5ed898252eaa50dcc01108ed4417c3ea98a294	refs/heads/special-subdir-.gitea
+c03543573ab088ce1cf7090a387d2be621426234	refs/heads/special-subdir-.github
+e75957ad9b7e6ed16dda183529ec283db0bbc5fe	refs/heads/special-subdir-docs
+46f5d5ab33d701642e08c713fab42af89fdd4fea	refs/heads/special-subdir-nested
+9c0f872256b839c2b97ec22fd348d87b14045513	refs/heads/subdir
+d7a854fff61e45b98234d7aa79ecbcb1619cd3dd	refs/heads/symlink
+30b9c0ed4b1039dbd99f3fb537b84ca507e0549d	refs/heads/symlink-loop
+41489b7be5c2244d2b7b524dcb31caf3bd1f9ccc	refs/heads/txt