Test artifact hashes as opaque values

internal/artifact/reader_test.go

@@ -3,9 +3,7 @@ package artifact
 import (
 	"bytes"
 	"context"
-	"crypto/sha256"
 	"errors"
-	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -284,9 +282,12 @@ func TestFileReaderUsesOpenedSizeOnlyAsACapacityHint(t *testing.T) {
 			if artifact.Name != filepath.Base(filePath) || artifact.URI != filePath || artifact.ContentType == "" {
 				t.Fatalf("unexpected artifact metadata: name=%q URI=%q content type=%q", artifact.Name, artifact.URI, artifact.ContentType)
 			}
-			wantHash := fmt.Sprintf("%x", sha256.Sum256(tc.body))
-			if artifact.Hash != wantHash {
-				t.Fatalf("artifact hash=%q, want %q", artifact.Hash, wantHash)
+			inline, err := NewCompositeReader().Read(context.Background(), domain.ArtifactRef{Type: domain.ArtifactRefInline, Body: string(tc.body)})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if inline.Hash == "" || artifact.Hash != inline.Hash {
+				t.Fatalf("file and inline hashes differ: %q/%q", artifact.Hash, inline.Hash)
 			}
 		})
 	}