diff --git a/Makefile b/Makefile
index f73d8d1..8315e20 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
 .PHONY: tests
 
 tests:
-	ZDOTDIR="${PWD}/tests" cram -i --shell=zsh tests/branch-bundle.t
+	ZDOTDIR="${PWD}/tests" cram -i --shell=zsh tests/branch-bundle.t \
+			tests/update.t
diff --git a/tests/.zshenv b/tests/.zshenv
index 7b5f699..859766f 100644
--- a/tests/.zshenv
+++ b/tests/.zshenv
@@ -9,7 +9,7 @@ if [[ ! -d "$default_clone" ]]; then
 fi
 
 export ANTIGEN_DEFAULT_REPO_URL="$default_clone"
-export ADOTDIR="$TMP/dot-antigen"
+export ADOTDIR="$PWD/dot-antigen"
 
 rm "$TESTDIR/.zcompdump"
 
diff --git a/tests/update.t b/tests/update.t
new file mode 100644
index 0000000..3849938
--- /dev/null
+++ b/tests/update.t
@@ -0,0 +1,62 @@
+Setup a plugin.
+
+  $ mkdir plugin
+
+A git wrapper that works with the plugin's repo.
+
+  $ pg () {
+  >   git --git-dir plugin/.git --work-tree plugin "$@"
+  > }
+
+Setup the plugin repo.
+
+  $ pg init
+  Initialized empty Git repository in .+?/plugin/\.git/? (re)
+
+Write to the plugin.
+
+  $ cat > plugin/aliases.zsh <<EOF
+  > alias hehe='echo hehe'
+  > EOF
+  $ pg add .
+  $ pg commit -m 'Initial commit'
+  \[master \(root-commit\) [a-f0-9]{7}\] Initial commit (re)
+   1 file changed, 1 insertion(+)
+   create mode [\d]{6} aliases\.zsh (re)
+
+Load plugin from master.
+
+  $ antigen-bundle $PWD/plugin
+  Cloning into '.+?'\.\.\. (re)
+  done.
+  $ hehe
+  hehe
+
+Update the plugin.
+
+  $ cat > plugin/aliases.zsh <<EOF
+  > alias hehe='echo hehe, updated'
+  > EOF
+  $ pg commit -am 'Updated message'
+  \[master [a-f0-9]{7}\] Updated message (re)
+   1 file changed, 1 insertion(+), 1 deletion(-)
+
+Update bundles.
+
+  $ antigen-update
+  From .+?/plugin (re)
+     [a-z0-9]{7}\.\.[a-z0-9]{7}  master     -> origin/master (re)
+  Updating [a-z0-9]{7}\.\.[a-z0-9]{7} (re)
+  Fast-forward
+   aliases.zsh |    2 +-
+   1 file changed, 1 insertion(+), 1 deletion(-)
+
+Confirm there is still only one repository.
+
+  $ ls $ADOTDIR/repos | wc -l
+  1
+
+The new alias should not activate.
+
+  $ hehe
+  hehe