test: add utility for file matching

test/e2e/internal/utils/exec.go

@@ -34,6 +34,7 @@ const (
 	Username       = "hello"
 	Password       = "oras-test"
 	AuthConfigPath = "test.config"
+	DefaultTimeout = 10 * time.Second
 )
 
 // ExecOption provides option used to execute a command.
@@ -61,7 +62,7 @@ func Binary(path string, args ...string) *ExecOption {
 	return &ExecOption{
 		binary:     path,
 		args:       args,
-		timeout:    10 * time.Second,
+		timeout:    DefaultTimeout,
 		shouldFail: false,
 	}
 }

test/e2e/internal/utils/file.go

@@ -18,6 +18,11 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"regexp"
+	"time"
+
+	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/gbytes"
 )
 
 var testFileRoot string
@@ -48,6 +53,16 @@ func CopyTestData(dstRoot string) error {
 	})
 }
 
+// MatchFile reads content from filepath, matches it with want with timeout.
+func MatchFile(filepath string, want string, timeout time.Duration) {
+	Expect(filepath).To(BeAnExistingFile())
+	f, err := os.Open(filepath)
+	Expect(err).ToNot(HaveOccurred())
+	defer f.Close()
+	want = regexp.QuoteMeta(want)
+	Eventually(gbytes.BufferReader(f)).WithTimeout(timeout).Should(gbytes.Say(want))
+}
+
 func copyFile(srcFile, dstFile string) error {
 	to, err := os.Create(dstFile)
 	if err != nil {

test/e2e/suite/command/manifest.go

@@ -85,8 +85,7 @@ var _ = Describe("Common registry users:", func() {
 			fetchPath := filepath.Join(GinkgoT().TempDir(), "fetchedImage")
 			ORAS("manifest", "fetch", Reference(Host, repo, multiImage), "--output", fetchPath, "--descriptor").
 				MatchContent(descriptor_multi).Exec()
-			Binary("cat", fetchPath).
-				MatchContent(manifest_multi).Exec()
+			MatchFile(fetchPath, manifest_multi, DefaultTimeout)
 		})
 
 		It("should fetch manifest via tag with platform selection", func() {

test/e2e/suite/command/push.go

@@ -16,6 +16,7 @@ package command
 import (
 	"bytes"
 	"fmt"
+	"path/filepath"
 
 	. "github.com/onsi/ginkgo/v2"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
@@ -84,10 +85,8 @@ var _ = Describe("Remote registry users:", func() {
 			ORAS("push", Reference(Host, repo, tag), files[1]+":"+layerType, "-v", "--export-manifest", exportPath).
 				MatchStatus(statusKeys, true, 2).
 				WithWorkDir(tempDir).Exec()
-			fetched := ORAS("manifest", "fetch", Reference(Host, repo, tag)).Exec().Out
-			Binary("cat", exportPath).
-				WithWorkDir(tempDir).
-				MatchTrimmedContent(string(fetched.Contents())).Exec()
+			fetched := ORAS("manifest", "fetch", Reference(Host, repo, tag)).Exec().Out.Contents()
+			MatchFile(filepath.Join(tempDir, exportPath), string(fetched), DefaultTimeout)
 		})
 
 		It("should push files with customized config file", func() {

test/e2e/suite/scenario/oci_image.go

@@ -55,10 +55,9 @@ var _ = Describe("OCI image user:", Ordered, func() {
 				WithWorkDir(tempDir).
 				WithDescription("push files with manifest exported").Exec()
 
-			session := Binary("cat", manifestName).WithWorkDir(tempDir).Exec()
-			ORAS("manifest", "fetch", Reference(Host, repo, tag)).
-				MatchContent(string(session.Out.Contents())).
-				WithDescription("fetch pushed manifest content").Exec()
+			fetched := ORAS("manifest", "fetch", Reference(Host, repo, tag)).
+				WithDescription("fetch pushed manifest content").Exec().Out.Contents()
+			MatchFile(filepath.Join(tempDir, manifestName), string(fetched), DefaultTimeout)
 
 			pullRoot := "pulled"
 			ORAS("pull", Reference(Host, repo, tag), "-v", "--config", files[0], "-o", pullRoot).