feat(discovery): tag-agnostic image name normalisation

internal/discovery/matching_test.go

@@ -0,0 +1,51 @@
+package discovery_test
+
+import (
+	"testing"
+
+	"github.com/shcizo/package-updater/internal/discovery"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNormaliseImage(t *testing.T) {
+	cases := []struct {
+		in   string
+		want string
+	}{
+		{"registry.example.com/myapp", "registry.example.com/myapp"},
+		{"registry.example.com/myapp:v1.2.3", "registry.example.com/myapp"},
+		{"registry.example.com/myapp:latest", "registry.example.com/myapp"},
+		{"registry.example.com/myapp@sha256:abc123", "registry.example.com/myapp"},
+		{"registry.example.com/myapp:v1.2.3@sha256:abc123", "registry.example.com/myapp"},
+		{"nginx", "nginx"},
+		{"nginx:1.25-alpine", "nginx"},
+		{"library/nginx:latest", "library/nginx"},
+		{"gcr.io/proj/svc:tag", "gcr.io/proj/svc"},
+		{"localhost:5000/myimg:v1", "localhost:5000/myimg"},
+	}
+	for _, c := range cases {
+		t.Run(c.in, func(t *testing.T) {
+			require.Equal(t, c.want, discovery.NormaliseImage(c.in))
+		})
+	}
+}
+
+func TestImagesMatch(t *testing.T) {
+	require.True(t, discovery.ImagesMatch(
+		"registry.example.com/myapp",
+		"registry.example.com/myapp:v1.2.3",
+	))
+	require.True(t, discovery.ImagesMatch(
+		"registry.example.com/myapp:v1.0.0",
+		"registry.example.com/myapp:v9.9.9",
+	))
+	require.False(t, discovery.ImagesMatch(
+		"registry.example.com/myapp",
+		"registry.example.com/otherapp",
+	))
+	// Case-sensitive per spec section 5.2
+	require.False(t, discovery.ImagesMatch(
+		"registry.example.com/MyApp",
+		"registry.example.com/myapp",
+	))
+}