+# Corruption tests follow. Make sure to remove all traces of the
+# specific corruption you test afterwards, lest a later test trip over
+# it.
+
+test_expect_success 'object with bad sha1' '
+ sha=$(echo blob | git hash-object -w --stdin) &&
+ echo $sha &&
+ old=$(echo $sha | sed "s+^..+&/+") &&
+ new=$(dirname $old)/ffffffffffffffffffffffffffffffffffffff &&
+ sha="$(dirname $new)$(basename $new)"
+ mv .git/objects/$old .git/objects/$new &&
+ git update-index --add --cacheinfo 100644 $sha foo &&
+ tree=$(git write-tree) &&
+ cmt=$(echo bogus | git commit-tree $tree) &&
+ git update-ref refs/heads/bogus $cmt &&
+ (git fsck 2>out; true) &&
+ grep "$sha.*corrupt" out &&
+ rm -f .git/objects/$new &&
+ git update-ref -d refs/heads/bogus &&
+ git read-tree -u --reset HEAD
+'
+
+test_expect_success 'branch pointing to non-commit' '
+ git rev-parse HEAD^{tree} > .git/refs/heads/invalid &&
+ git fsck 2>out &&
+ grep "not a commit" out &&
+ git update-ref -d refs/heads/invalid
+'
+
+cat > invalid-tag <<EOF
+object ffffffffffffffffffffffffffffffffffffffff
+type commit
+tag invalid
+tagger T A Gger <tagger@example.com> 1234567890 -0000
+
+This is an invalid tag.
+EOF
+
+test_expect_failure 'tag pointing to nonexistent' '
+ tag=$(git hash-object -w --stdin < invalid-tag) &&
+ echo $tag > .git/refs/tags/invalid &&
+ git fsck --tags 2>out &&
+ cat out &&
+ grep "could not load tagged object" out &&
+ rm .git/refs/tags/invalid
+'
+
+cat > wrong-tag <<EOF
+object $(echo blob | git hash-object -w --stdin)
+type commit
+tag wrong
+tagger T A Gger <tagger@example.com> 1234567890 -0000
+
+This is an invalid tag.
+EOF
+
+test_expect_failure 'tag pointing to something else than its type' '
+ tag=$(git hash-object -w --stdin < wrong-tag) &&
+ echo $tag > .git/refs/tags/wrong &&
+ git fsck --tags 2>out &&
+ cat out &&
+ grep "some sane error message" out &&
+ rm .git/refs/tags/wrong
+'
+
+
+