internal/pkg: verify checksum after uneventful scrub

This checks that scrub did not condemn any entry without reporting it.

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

internal/pkg/pkg_test.go

@@ -202,6 +202,15 @@ func checkWithCache(t *testing.T, testCases []cacheTestCase) {
 				scrubFunc = c.Scrub
 			}
 
+			var restoreTemp bool
+			if _, err := os.Lstat(base.Append("temp").String()); err != nil {
+				if !errors.Is(err, os.ErrNotExist) {
+					t.Fatal(err)
+				}
+			} else {
+				restoreTemp = true
+			}
+
 			if checksum, err := pkg.HashDir(base); err != nil {
 				t.Fatalf("HashDir: error = %v", err)
 			} else if checksum != tc.want {
@@ -214,6 +223,25 @@ func checkWithCache(t *testing.T, testCases []cacheTestCase) {
 			if err := scrubFunc(); err != nil {
 				t.Fatal("cache contains inconsistencies\n\n" + err.Error())
 			}
+
+			if restoreTemp {
+				if err := os.Mkdir(
+					base.Append("temp").String(),
+					0700,
+				); err != nil {
+					t.Fatal(err)
+				}
+			}
+
+			// validate again to make sure scrub did not condemn anything
+			if checksum, err := pkg.HashDir(base); err != nil {
+				t.Fatalf("HashDir: error = %v", err)
+			} else if checksum != tc.want {
+				t.Fatalf("(scrubbed) HashDir: %v", &pkg.ChecksumMismatchError{
+					Got:  checksum,
+					Want: tc.want,
+				})
+			}
 		})
 	}
 }