ci: use only latest version of test status in retest action

Github's list statuses returns list of all status, possibly
containing dupicates and previously failed statuses.
Use "UpdatedAt" timestamp to only get the latest status
for each test.

Signed-off-by: Rakshith R <rar@redhat.com>

actions/retest/main.go

@@ -142,7 +142,9 @@ func main() {
 					continue
 				}
 
-				for _, r := range rs {
+				statusList := filterStatusList(rs)
+
+				for _, r := range statusList {
 					log.Printf("found context %s with status %s\n", r.GetContext(), r.GetState())
 					if contains([]string{"failed", "failure"}, r.GetState()) {
 						log.Printf("found failed test %s\n", r.GetContext())
@@ -233,3 +235,23 @@ func contains(s []string, e string) bool {
 
 	return false
 }
+
+// filterStatusesList returns list of unique and recently updated github RepoStatuses.
+// Raw github RepoStatus list may contain duplicate and older statuses.
+func filterStatusList(rawStatusList []*github.RepoStatus) []*github.RepoStatus {
+	testStatus := make(map[string]*github.RepoStatus)
+
+	for _, r := range rawStatusList {
+		status, ok := testStatus[r.GetContext()]
+		if !ok || r.GetUpdatedAt().After(status.GetUpdatedAt()) {
+			testStatus[r.GetContext()] = r
+		}
+	}
+
+	statusList := make([]*github.RepoStatus, 0)
+	for _, rs := range testStatus {
+		statusList = append(statusList, rs)
+	}
+
+	return statusList
+}