diff --git a/tests/helpers.sh b/tests/helpers.sh
index 397c607..122347a 100644
--- a/tests/helpers.sh
+++ b/tests/helpers.sh
@@ -35,6 +35,16 @@ check_dir_exists_helper() {
 	fi
 }
 
+# runs the scripts and asserts it has the correct output and exit code
+script_run_helper() {
+	local script="$1"
+	local expected_output="$2"
+	local expected_exit_code="${3:-0}"
+	"$script" |
+		grep "$expected_output" >/dev/null 2>&1 && # grep -q flag quits the script early
+		[ "${PIPESTATUS[0]}" -eq "$expected_exit_code" ]
+}
+
 fail_helper() {
 	local message="$1"
 	echo "$message" >&2
diff --git a/tests/test_plugin_installation.sh b/tests/test_plugin_installation.sh
index 994f318..35c20ff 100755
--- a/tests/test_plugin_installation.sh
+++ b/tests/test_plugin_installation.sh
@@ -4,7 +4,9 @@ CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 source $CURRENT_DIR/helpers.sh
 
-test_plugin_installation() {
+# TMUX KEY-BINDING TESTS
+
+test_plugin_installation_via_tmux_key_binding() {
 	set_tmux_conf_helper <<- HERE
 	set -g @plugin "tmux-plugins/tmux-example-plugin"
 	run-shell "$PWD/tpm"
@@ -12,16 +14,16 @@ test_plugin_installation() {
 
 	# opens tmux and test it with `expect`
 	"$CURRENT_DIR"/expect_successful_plugin_download ||
-		fail_helper "Tmux plugin installation fails"
+		fail_helper "[key-binding] plugin installation fails"
 
 	# check plugin dir exists after download
 	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
-		fail_helper "Plugin download fails"
+		fail_helper "[key-binding] plugin download fails"
 
 	teardown_helper
 }
 
-test_multiple_plugins_installation() {
+test_multiple_plugins_installation_via_tmux_key_binding() {
 	set_tmux_conf_helper <<- HERE
 	set -g @plugin "tmux-plugins/tmux-example-plugin"
 	\ \ set  -g    @plugin 'tmux-plugins/tmux-copycat'
@@ -30,21 +32,66 @@ test_multiple_plugins_installation() {
 
 	# opens tmux and test it with `expect`
 	"$CURRENT_DIR"/expect_successful_multiple_plugins_download ||
-		fail_helper "Tmux multiple plugins installation fails"
+		fail_helper "[key-binding] multiple plugins installation fails"
 
-	# check plugin dir exists after download
 	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
-		fail_helper "Plugin download fails (tmux-example-plugin)"
+		fail_helper "[key-binding] plugin download fails (tmux-example-plugin)"
 
 	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
-		fail_helper "Plugin download fails (tmux-copycat)"
+		fail_helper "[key-binding] plugin download fails (tmux-copycat)"
+
+	teardown_helper
+}
+
+# SCRIPT TESTS
+
+test_plugin_installation_via_script() {
+	set_tmux_conf_helper <<- HERE
+	set -g @plugin "tmux-plugins/tmux-example-plugin"
+	run-shell "$PWD/tpm"
+	HERE
+
+	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+		fail_helper "[script] plugin installation fails"
+
+	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+		fail_helper "[script] plugin download fails"
+
+	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-example-plugin"' ||
+		fail_helper "[script] plugin already installed message fail"
+
+	teardown_helper
+}
+
+test_multiple_plugins_installation_via_script() {
+	set_tmux_conf_helper <<- HERE
+	set -g @plugin "tmux-plugins/tmux-example-plugin"
+	\ \ set  -g    @plugin 'tmux-plugins/tmux-copycat'
+	run-shell "$PWD/tpm"
+	HERE
+
+	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+		fail_helper "[script] multiple plugins installation fails"
+
+	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+		fail_helper "[script] plugin download fails (tmux-example-plugin)"
+
+	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
+		fail_helper "[script] plugin download fails (tmux-copycat)"
+
+	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-copycat"' ||
+		fail_helper "[script] multiple plugins already installed message fail"
 
 	teardown_helper
 }
 
 main() {
-	test_plugin_installation
-	test_multiple_plugins_installation
+	test_plugin_installation_via_tmux_key_binding
+	test_multiple_plugins_installation_via_tmux_key_binding
+
+	test_plugin_installation_via_script
+	test_multiple_plugins_installation_via_script
+
 	exit_value_helper
 }
 main
diff --git a/tests/test_plugin_installation_legacy.sh b/tests/test_plugin_installation_legacy.sh
index 6627b85..aeec737 100755
--- a/tests/test_plugin_installation_legacy.sh
+++ b/tests/test_plugin_installation_legacy.sh
@@ -4,7 +4,9 @@ CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 source $CURRENT_DIR/helpers.sh
 
-test_plugin_installation() {
+# TMUX KEY-BINDING TESTS
+
+test_plugin_installation_via_tmux_key_binding() {
 	set_tmux_conf_helper <<- HERE
 	set -g @tpm_plugins "tmux-plugins/tmux-example-plugin"
 	run-shell "$PWD/tpm"
@@ -12,16 +14,16 @@ test_plugin_installation() {
 
 	# opens tmux and test it with `expect`
 	$CURRENT_DIR/expect_successful_plugin_download ||
-		fail_helper "Tmux plugin installation fails"
+		fail_helper "[key-binding] plugin installation fails"
 
 	# check plugin dir exists after download
 	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
-		fail_helper "Plugin download fails"
+		fail_helper "[key-binding] plugin download fails"
 
 	teardown_helper
 }
 
-test_legacy_and_new_syntax_for_plugin_installation_work() {
+test_legacy_and_new_syntax_for_plugin_installation_work_via_tmux_key_binding() {
 	set_tmux_conf_helper <<- HERE
 	set -g @tpm_plugins "                   \
 		tmux-plugins/tmux-example-plugin    \
@@ -32,21 +34,69 @@ test_legacy_and_new_syntax_for_plugin_installation_work() {
 
 	# opens tmux and test it with `expect`
 	"$CURRENT_DIR"/expect_successful_multiple_plugins_download ||
-		fail_helper "Tmux multiple plugins installation fails"
+		fail_helper "[key-binding] multiple plugins installation fails"
 
 	# check plugin dir exists after download
 	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
-		fail_helper "Plugin download fails (tmux-example-plugin)"
+		fail_helper "[key-binding] plugin download fails (tmux-example-plugin)"
 
 	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
-		fail_helper "Plugin download fails (tmux-copycat)"
+		fail_helper "[key-binding] plugin download fails (tmux-copycat)"
+
+	teardown_helper
+}
+
+# SCRIPT TESTS
+
+test_plugin_installation_via_script() {
+	set_tmux_conf_helper <<- HERE
+	set -g @tpm_plugins "tmux-plugins/tmux-example-plugin"
+	run-shell "$PWD/tpm"
+	HERE
+
+	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+		fail_helper "[script] plugin installation fails"
+
+	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+		fail_helper "[script] plugin download fails"
+
+	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-example-plugin"' ||
+		fail_helper "[script] plugin already installed message fail"
+
+	teardown_helper
+}
+
+test_legacy_and_new_syntax_for_plugin_installation_work_via_script() {
+	set_tmux_conf_helper <<- HERE
+	set -g @tpm_plugins "                   \
+		tmux-plugins/tmux-example-plugin    \
+	"
+	set -g @plugin 'tmux-plugins/tmux-copycat'
+	run-shell "$PWD/tpm"
+	HERE
+
+	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+		fail_helper "[script] multiple plugin installation fails"
+
+	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+		fail_helper "[script] plugin download fails (tmux-example-plugin)"
+
+	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
+		fail_helper "[script] plugin download fails (tmux-copycat)"
+
+	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-copycat"' ||
+		fail_helper "[script] multiple plugins already installed message fail"
 
 	teardown_helper
 }
 
 main() {
-	test_plugin_installation
-	test_legacy_and_new_syntax_for_plugin_installation_work
+	test_plugin_installation_via_tmux_key_binding
+	test_legacy_and_new_syntax_for_plugin_installation_work_via_tmux_key_binding
+
+	test_plugin_installation_via_script
+	test_legacy_and_new_syntax_for_plugin_installation_work_via_script
+
 	exit_value_helper
 }
 main