diff --git a/tests/_autoenv_stack.t b/tests/_autoenv_stack.t
index dd56fff..580176c 100644
--- a/tests/_autoenv_stack.t
+++ b/tests/_autoenv_stack.t
@@ -1,6 +1,6 @@
 Tests for internal stack handling.
 
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Non-existing entries are allowed and handled without error.
 
diff --git a/tests/_autoenv_utils.t b/tests/_autoenv_utils.t
index 303cd24..3c00b00 100644
--- a/tests/_autoenv_utils.t
+++ b/tests/_autoenv_utils.t
@@ -1,6 +1,6 @@
 Tests for internal util methods.
 
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Non-existing entries are allowed and handled without error.
 
diff --git a/tests/autoenv.t b/tests/autoenv.t
index 67be7ca..b0c520f 100644
--- a/tests/autoenv.t
+++ b/tests/autoenv.t
@@ -1,4 +1,4 @@
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Lets set a simple .env action
 
diff --git a/tests/cwd.t b/tests/cwd.t
index 9a0bd13..4c02fbf 100644
--- a/tests/cwd.t
+++ b/tests/cwd.t
@@ -1,6 +1,6 @@
 Test $PWD, $autoenv_event, $autoenv_from_dir and $autoenv_to_dir.
 
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Setup env actions / output.
 
diff --git a/tests/leave.t b/tests/leave.t
index ad70e2f..473a273 100644
--- a/tests/leave.t
+++ b/tests/leave.t
@@ -1,4 +1,4 @@
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Lets set a simple .env action
 
diff --git a/tests/recurse-upwards.t b/tests/recurse-upwards.t
index 20a35d1..2294293 100644
--- a/tests/recurse-upwards.t
+++ b/tests/recurse-upwards.t
@@ -1,6 +1,6 @@
 Test recursing into parent .env files.
 
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Setup env actions / output.
 
diff --git a/tests/setup.sh b/tests/setup.zsh
similarity index 100%
rename from tests/setup.sh
rename to tests/setup.zsh
diff --git a/tests/varstash.t b/tests/varstash.t
index 85d665f..b75aa59 100644
--- a/tests/varstash.t
+++ b/tests/varstash.t
@@ -1,6 +1,6 @@
 Test varstash integration.
 
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Setup test environment.
 
diff --git a/tests/varstash_export.t b/tests/varstash_export.t
index 2b75848..b8e70f7 100644
--- a/tests/varstash_export.t
+++ b/tests/varstash_export.t
@@ -1,6 +1,6 @@
 Test varstash with exported variables in subshell.
 
-  $ source $TESTDIR/setup.sh || return 1
+  $ source $TESTDIR/setup.zsh || return 1
 
 Setup test environment.