Centralize source manifest validation

internal/bundle/manifest_test.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"strings"
 	"testing"
+	"time"
 
 	"gitea.maximumdirect.net/eric/distributor/internal/storage"
 )
@@ -92,6 +93,75 @@ func TestParseManifestRejectsDuplicatePaths(t *testing.T) {
 	assertErrorContains(t, err, "duplicates")
 }
 
+func TestValidateManifestAcceptsValidFixture(t *testing.T) {
+	manifest := validFixtureManifest(t)
+	if err := ValidateManifest(manifest); err != nil {
+		t.Fatalf("ValidateManifest() error = %v", err)
+	}
+}
+
+func TestValidateManifestRejectsInvalidManifest(t *testing.T) {
+	tests := map[string]func(Manifest) Manifest{
+		"schema version": func(manifest Manifest) Manifest {
+			manifest.SchemaVersion = 2
+			return manifest
+		},
+		"empty id": func(manifest Manifest) Manifest {
+			manifest.ID = ""
+			return manifest
+		},
+		"bad digest": func(manifest Manifest) Manifest {
+			manifest.Digest = "SHA256:099b205780d2b050024868399961b05731729a548d5d6329c7b06a6740dd75fe"
+			return manifest
+		},
+		"zero created": func(manifest Manifest) Manifest {
+			manifest.Created = time.Time{}
+			return manifest
+		},
+		"empty files": func(manifest Manifest) Manifest {
+			manifest.Files = nil
+			manifest.Digest = BundleDigest(manifest.Files)
+			return manifest
+		},
+		"unsafe path": func(manifest Manifest) Manifest {
+			manifest.Files[0].Path = "../report.md"
+			manifest.Digest = BundleDigest(manifest.Files)
+			return manifest
+		},
+		"duplicate path": func(manifest Manifest) Manifest {
+			manifest.Files[1].Path = manifest.Files[0].Path
+			manifest.Digest = BundleDigest(manifest.Files)
+			return manifest
+		},
+		"negative size": func(manifest Manifest) Manifest {
+			manifest.Files[0].Size = -1
+			manifest.Digest = BundleDigest(manifest.Files)
+			return manifest
+		},
+		"digest mismatch": func(manifest Manifest) Manifest {
+			manifest.Digest = "sha256:0000000000000000000000000000000000000000000000000000000000000000"
+			return manifest
+		},
+	}
+	for name, mutate := range tests {
+		t.Run(name, func(t *testing.T) {
+			err := ValidateManifest(mutate(validFixtureManifest(t)))
+			if err == nil {
+				t.Fatal("ValidateManifest() error = nil, want error")
+			}
+		})
+	}
+}
+
+func validFixtureManifest(t *testing.T) Manifest {
+	t.Helper()
+	manifest, err := ParseManifest(readFixture(t, "testdata/valid_bundle/manifest.json"))
+	if err != nil {
+		t.Fatalf("ParseManifest() error = %v", err)
+	}
+	return manifest
+}
+
 func readFixture(t *testing.T, path string) []byte {
 	t.Helper()
 	data, err := os.ReadFile(path)