diff --git a/test/lib/env-test.sh b/test/lib/env-test.sh
index a445044..a1766ad 100755
--- a/test/lib/env-test.sh
+++ b/test/lib/env-test.sh
@@ -5,10 +5,6 @@ source "../test-helper.sh"
 # env.sh tests.
 #
 
-# Setup
-TMUXIFIER="/path/to/tmuxifier"
-unset TMUXIFIER_LAYOUT_PATH
-
 # When TMUXIFIER_LAYOUT_PATH is not set.
 source "../../lib/env.sh"
 assert 'echo $TMUXIFIER_LAYOUT_PATH' "${TMUXIFIER}/layouts"
@@ -26,8 +22,5 @@ assert 'echo $TMUXIFIER_LAYOUT_PATH' "/path/to/layouts"
 unset TMUXIFIER_LAYOUT_PATH
 
 
-# Teardown
-unset TMUXIFIER
-
 # End of tests.
 assert_end "env.sh"
diff --git a/test/test-helper.sh b/test/test-helper.sh
index 30fbcd9..0b37170 100644
--- a/test/test-helper.sh
+++ b/test/test-helper.sh
@@ -3,6 +3,15 @@
 # Set testroot variable.
 testroot="$(dirname "$BASH_SOURCE")"
 
+# Set TMUXIFIER environment variable
+TMUXIFIER="$(dirname "$testroot")"
+
+# Unset various Tmuxifier environment variables to prevent a local install of
+# Tmuxifier interfering with tests.
+unset TMUXIFIER_LAYOUT_PATH
+unset TMUXIFIER_TMUX_OPTS
+unset TMUXIFIER_NO_COMPLETE
+
 # Include assert.sh and stub.sh libraries.
 source "${testroot}/assert.sh"
 source "${testroot}/stub.sh"