Test artifact hashes as opaque values

docs/roadmap/implementation.md

@@ -757,6 +757,10 @@ second catalog matrix. Focused bundle tests pass on Go 1.27.3.
 meaningful without choosing an opaque value's algorithm. Keep benchmark setup
 outside timed work and do not add a new encoding guarantee.
 
+Completion: size-hint tests and benchmark correctness setup compare file hashes
+to the same content read inline, without selecting a hash algorithm. Artifact
+tests and one-iteration checks of both benchmark paths pass on Go 1.27.3.
+
 ## Stage 30: Remove Unconsumed State And Orphan Helpers
 
 **Catalog:** 30, remaining half of 32, 33.

internal/artifact/reader_benchmark_test.go

@@ -3,8 +3,6 @@ package artifact
 import (
 	"bytes"
 	"context"
-	"crypto/sha256"
-	"fmt"
 	"mime"
 	"os"
 	"path/filepath"
@@ -153,9 +151,12 @@ func checkArtifactFileRead(b *testing.B, reader Reader, ref domain.ArtifactRef,
 	if !bytes.Equal(artifact.Body, want) || artifact.Size != int64(len(want)) {
 		b.Fatalf("artifact size=%d body length=%d, want %d", artifact.Size, len(artifact.Body), len(want))
 	}
-	wantHash := fmt.Sprintf("%x", sha256.Sum256(want))
-	if artifact.Hash != wantHash {
-		b.Fatalf("artifact hash=%q, want %q", artifact.Hash, wantHash)
+	inline, err := NewCompositeReader().Read(context.Background(), domain.ArtifactRef{Type: domain.ArtifactRefInline, Body: string(want)})
+	if err != nil {
+		b.Fatal(err)
+	}
+	if inline.Hash == "" || artifact.Hash != inline.Hash {
+		b.Fatalf("file and inline hashes differ: %q/%q", artifact.Hash, inline.Hash)
 	}
 }
 

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)
 			}
 		})
 	}