internal/pkg: expose underlying reader

This will be fully implemented in httpArtifact in a future commit.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/pkg_test.go

@@ -47,10 +47,10 @@ type overrideIdent struct {
 
 func (a overrideIdent) ID() pkg.ID { return a.id }
 
-// overrideIdentFile overrides the ID method of [File].
+// overrideIdentFile overrides the ID method of [FileArtifact].
 type overrideIdentFile struct {
 	id pkg.ID
-	pkg.File
+	pkg.FileArtifact
 }
 
 func (a overrideIdentFile) ID() pkg.ID { return a.id }
@@ -61,10 +61,10 @@ type knownIdentArtifact interface {
 	pkg.TrivialArtifact
 }
 
-// A knownIdentFile implements [pkg.KnownIdent] and [File]
+// A knownIdentFile implements [pkg.KnownIdent] and [FileArtifact]
 type knownIdentFile interface {
 	pkg.KnownIdent
-	pkg.File
+	pkg.FileArtifact
 }
 
 // overrideChecksum overrides the Checksum method of [Artifact].
@@ -75,7 +75,7 @@ type overrideChecksum struct {
 
 func (a overrideChecksum) Checksum() pkg.Checksum { return a.checksum }
 
-// overrideChecksumFile overrides the Checksum method of [File].
+// overrideChecksumFile overrides the Checksum method of [FileArtifact].
 type overrideChecksumFile struct {
 	checksum pkg.Checksum
 	knownIdentFile
@@ -111,7 +111,7 @@ func (a *stubArtifactF) Params(ctx *pkg.IContext)     { ctx.GetHash().Write(a.pa
 func (a *stubArtifactF) Dependencies() []pkg.Artifact { return a.deps }
 func (a *stubArtifactF) Cure(f *pkg.FContext) error   { return a.cure(f) }
 
-// A stubFile implements [File] with hardcoded behaviour.
+// A stubFile implements [FileArtifact] with hardcoded behaviour.
 type stubFile struct {
 	data []byte
 	err  error
@@ -119,7 +119,9 @@ type stubFile struct {
 	stubArtifact
 }
 
-func (a *stubFile) Cure(context.Context) ([]byte, error) { return a.data, a.err }
+func (a *stubFile) Cure(context.Context) (io.ReadCloser, error) {
+	return io.NopCloser(bytes.NewReader(a.data)), a.err
+}
 
 // newStubFile returns an implementation of [pkg.File] with hardcoded behaviour.
 func newStubFile(
@@ -128,7 +130,7 @@ func newStubFile(
 	sum *pkg.Checksum,
 	data []byte,
 	err error,
-) pkg.File {
+) pkg.FileArtifact {
 	f := overrideIdentFile{id, &stubFile{data, err, stubArtifact{
 		kind,
 		nil,