From 0bd12e447450470bff7df9486297827371109bb3 Mon Sep 17 00:00:00 2001
From: Matej Vasek <mvasek@redhat.com>
Date: Thu, 13 Jul 2023 21:03:41 +0200
Subject: [PATCH] test: OCI content created by "host" builder

Signed-off-by: Matej Vasek <mvasek@redhat.com>
---
 pkg/oci/builder_test.go | 93 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 89 insertions(+), 4 deletions(-)

diff --git a/pkg/oci/builder_test.go b/pkg/oci/builder_test.go
index 0def0164a1..a8cfc2c9a3 100644
--- a/pkg/oci/builder_test.go
+++ b/pkg/oci/builder_test.go
@@ -1,15 +1,22 @@
 package oci
 
 import (
+	"archive/tar"
+	"compress/gzip"
 	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"runtime"
+	"sort"
+	"strings"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 	fn "knative.dev/func/pkg/functions"
 	. "knative.dev/func/pkg/testing"
@@ -172,8 +179,86 @@ func validateOCI(path string, t *testing.T) {
 		t.Fatalf("invalid schema version, expected 2, got %d", imageIndex.SchemaVersion)
 	}
 
-	// Additional validation of the Image Index structure can be added here
-	// extract. for example checking that the path includes the README.md
-	// and one of the binaries in the exact location expected (the data layer
-	// blob and exec layer blob, respectively)
+	if len(imageIndex.Manifests) < 1 {
+		t.Fatal("fewer manifests")
+	}
+
+	digestParts := strings.SplitN(imageIndex.Manifests[0].Digest, ":", 2)
+	if len(digestParts) < 2 {
+		t.Fatal("invalid digest format")
+	}
+	manifestFile := filepath.Join(path, "blobs", "sha256", digestParts[1])
+	manifestFileData, err := os.ReadFile(manifestFile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	mf := struct {
+		Layers []struct {
+			Digest string `json:"digest"`
+		} `json:"layers"`
+	}{}
+	err = json.Unmarshal(manifestFileData, &mf)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	type fileInfo struct {
+		Path string
+		Mod  fs.FileMode
+	}
+	var files []fileInfo
+
+	for _, layer := range mf.Layers {
+		func() {
+			digestParts = strings.SplitN(layer.Digest, ":", 2)
+			if len(digestParts) < 2 {
+				t.Fatal("invalid digest format")
+			}
+			f, err := os.Open(filepath.Join(path, "blobs", "sha256", digestParts[1]))
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer f.Close()
+
+			gr, err := gzip.NewReader(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer gr.Close()
+
+			tr := tar.NewReader(gr)
+			for {
+				hdr, err := tr.Next()
+				if err != nil {
+					if errors.Is(err, io.EOF) {
+						break
+					}
+					t.Fatal(err)
+				}
+				files = append(files, fileInfo{
+					Path: hdr.Name,
+					Mod:  hdr.FileInfo().Mode() & (fs.ModeType | fs.ModePerm),
+				})
+			}
+		}()
+	}
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].Path < files[j].Path
+	})
+
+	expectedFiles := []fileInfo{
+		{Path: "/etc/pki/tls/certs/ca-certificates.crt", Mod: 0644},
+		{Path: "/etc/ssl/certs/ca-certificates.crt", Mod: 0644},
+		{Path: "/func", Mod: 0755 | fs.ModeDir},
+		{Path: "/func/README.md", Mod: 0644},
+		{Path: "/func/f", Mod: 0755},
+		{Path: "/func/func.yaml", Mod: 0644},
+		{Path: "/func/go.mod", Mod: 0644},
+		{Path: "/func/handle.go", Mod: 0644},
+		{Path: "/func/handle_test.go", Mod: 0644},
+	}
+
+	if diff := cmp.Diff(expectedFiles, files); diff != "" {
+		t.Error("files in oci differ from expectation (-want, +got):", diff)
+	}
 }