1 files changed, 129 insertions, 0 deletions
diff --git a/backend/feed/discover_test.go b/backend/feed/discover_test.go
new file mode 100644
index 0000000..4a1315e
--- /dev/null
+++ b/backend/feed/discover_test.go
@@ -0,0 +1,129 @@
+package feed
+
+import (
+	"net/url"
+	"strings"
+	"testing"
+)
+
+func mustParseURL(s string) *url.URL {
+	u, err := url.Parse(s)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}
+
+func TestDiscoverFeeds_AtomAndRSS(t *testing.T) {
+	html := `<!DOCTYPE html>
+<html>
+<head>
+    <link rel="alternate" type="application/atom+xml" href="/feed.atom" title="Atom Feed">
+    <link rel="alternate" type="application/rss+xml" href="/feed.rss" title="RSS Feed">
+</head>
+<body></body>
+</html>`
+
+	base := mustParseURL("https://example.com/blog")
+	links := discoverFeeds(strings.NewReader(html), base)
+
+	if len(links) != 2 {
+		t.Fatalf("expected 2 links, got %d", len(links))
+	}
+	if links[0].URL != "https://example.com/feed.atom" || links[0].Type != "atom" {
+		t.Errorf("unexpected first link: %+v", links[0])
+	}
+	if links[1].URL != "https://example.com/feed.rss" || links[1].Type != "rss" {
+		t.Errorf("unexpected second link: %+v", links[1])
+	}
+}
+
+func TestDiscoverFeeds_AbsoluteURL(t *testing.T) {
+	html := `<html><head>
+    <link rel="alternate" type="application/atom+xml" href="https://other.com/feed.xml">
+</head><body></body></html>`
+
+	base := mustParseURL("https://example.com")
+	links := discoverFeeds(strings.NewReader(html), base)
+
+	if len(links) != 1 {
+		t.Fatalf("expected 1 link, got %d", len(links))
+	}
+	if links[0].URL != "https://other.com/feed.xml" {
+		t.Errorf("expected absolute URL preserved, got %s", links[0].URL)
+	}
+}
+
+func TestDiscoverFeeds_NoFeeds(t *testing.T) {
+	html := `<html><head><title>No feeds</title></head><body></body></html>`
+	links := discoverFeeds(strings.NewReader(html), mustParseURL("https://example.com"))
+	if len(links) != 0 {
+		t.Fatalf("expected 0 links, got %d", len(links))
+	}
+}
+
+func TestDiscoverFeeds_IgnoresNonAlternate(t *testing.T) {
+	html := `<html><head>
+    <link rel="stylesheet" type="text/css" href="/style.css">
+    <link rel="alternate" type="application/atom+xml" href="/feed.atom">
+</head><body></body></html>`
+
+	links := discoverFeeds(strings.NewReader(html), mustParseURL("https://example.com"))
+	if len(links) != 1 {
+		t.Fatalf("expected 1 link, got %d", len(links))
+	}
+}
+
+func TestDiscoverFeeds_IgnoresUnknownTypes(t *testing.T) {
+	html := `<html><head>
+    <link rel="alternate" type="application/json" href="/feed.json">
+    <link rel="alternate" type="application/rss+xml" href="/feed.rss">
+</head><body></body></html>`
+
+	links := discoverFeeds(strings.NewReader(html), mustParseURL("https://example.com"))
+	if len(links) != 1 {
+		t.Fatalf("expected 1 link, got %d", len(links))
+	}
+	if links[0].Type != "rss" {
+		t.Errorf("expected rss, got %s", links[0].Type)
+	}
+}
+
+func TestDiscoverFeeds_StopsAtBody(t *testing.T) {
+	html := `<html><head></head><body>
+    <link rel="alternate" type="application/atom+xml" href="/feed.atom">
+</body></html>`
+
+	links := discoverFeeds(strings.NewReader(html), mustParseURL("https://example.com"))
+	if len(links) != 0 {
+		t.Fatalf("expected 0 links (should stop at body), got %d", len(links))
+	}
+}
+
+func TestSelectFeed_PrefersAtom(t *testing.T) {
+	links := []feedLink{
+		{URL: "https://example.com/rss", Type: "rss"},
+		{URL: "https://example.com/atom", Type: "atom"},
+	}
+	got := selectFeed(links)
+	if got != "https://example.com/atom" {
+		t.Errorf("expected Atom URL, got %s", got)
+	}
+}
+
+func TestSelectFeed_FallsBackToRSS(t *testing.T) {
+	links := []feedLink{
+		{URL: "https://example.com/rss", Type: "rss"},
+	}
+	got := selectFeed(links)
+	if got != "https://example.com/rss" {
+		t.Errorf("expected RSS URL, got %s", got)
+	}
+}
+
+func TestSelectFeed_EmptyList(t *testing.T) {
+	got := selectFeed(nil)
+	if got != "" {
+		t.Errorf("expected empty string, got %s", got)
+	}
+}