diff --git a/tests/run-tests-within-vm b/tests/run-tests-within-vm
index 224a07c..d2a5755 100755
--- a/tests/run-tests-within-vm
+++ b/tests/run-tests-within-vm
@@ -24,7 +24,7 @@ run_tests() {
 	local test_file
 	for test_file in $(test_files); do
 		echo "Running test: $test_file"
-		$CURRENT_DIR/$test_file
+		"$CURRENT_DIR/$test_file"
 
 		# handling exit value
 		local exit_value="$?"
diff --git a/tests/test_plugin_clean.sh b/tests/test_plugin_clean.sh
index 3d579a0..d47564a 100755
--- a/tests/test_plugin_clean.sh
+++ b/tests/test_plugin_clean.sh
@@ -1,25 +1,27 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+TPM_DIR="$PWD"
+PLUGINS_DIR="$HOME/.tmux/plugins"
 
-source "$CURRENT_DIR"/helpers.sh
+source "$CURRENT_DIR/helpers.sh"
 
 manually_install_the_plugin() {
-	rm -rf   ~/.tmux/plugins/
-	mkdir -p ~/.tmux/plugins/
-	cd ~/.tmux/plugins/
+	rm -rf "$PLUGINS_DIR"
+	mkdir -p "$PLUGINS_DIR"
+	cd "$PLUGINS_DIR"
 	git clone --quiet https://github.com/tmux-plugins/tmux-example-plugin
 }
 
 test_plugin_installation() {
 	set_tmux_conf_helper <<- HERE
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	manually_install_the_plugin
 
 	# opens tmux and test it with `expect`
-	"$CURRENT_DIR"/expect_successful_clean_plugins ||
+	"$CURRENT_DIR/expect_successful_clean_plugins" ||
 		fail_helper "Clean fails"
 
 	teardown_helper
diff --git a/tests/test_plugin_installation.sh b/tests/test_plugin_installation.sh
index 35c20ff..3953a84 100755
--- a/tests/test_plugin_installation.sh
+++ b/tests/test_plugin_installation.sh
@@ -1,15 +1,17 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+PLUGINS_DIR="$HOME/.tmux/plugins"
+TPM_DIR="$PWD"
 
-source $CURRENT_DIR/helpers.sh
+source "$CURRENT_DIR/helpers.sh"
 
 # 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 "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	# opens tmux and test it with `expect`
@@ -17,7 +19,7 @@ test_plugin_installation_via_tmux_key_binding() {
 		fail_helper "[key-binding] plugin installation fails"
 
 	# check plugin dir exists after download
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[key-binding] plugin download fails"
 
 	teardown_helper
@@ -27,17 +29,17 @@ 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'
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	# opens tmux and test it with `expect`
 	"$CURRENT_DIR"/expect_successful_multiple_plugins_download ||
 		fail_helper "[key-binding] multiple plugins installation fails"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[key-binding] plugin download fails (tmux-example-plugin)"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-copycat/" ||
 		fail_helper "[key-binding] plugin download fails (tmux-copycat)"
 
 	teardown_helper
@@ -48,16 +50,16 @@ test_multiple_plugins_installation_via_tmux_key_binding() {
 test_plugin_installation_via_script() {
 	set_tmux_conf_helper <<- HERE
 	set -g @plugin "tmux-plugins/tmux-example-plugin"
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
-	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" '"tmux-example-plugin" download success' ||
 		fail_helper "[script] plugin installation fails"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[script] plugin download fails"
 
-	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-example-plugin"' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" 'Already installed "tmux-example-plugin"' ||
 		fail_helper "[script] plugin already installed message fail"
 
 	teardown_helper
@@ -67,19 +69,19 @@ 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 "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
-	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" '"tmux-example-plugin" download success' ||
 		fail_helper "[script] multiple plugins installation fails"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[script] plugin download fails (tmux-example-plugin)"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-copycat/" ||
 		fail_helper "[script] plugin download fails (tmux-copycat)"
 
-	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-copycat"' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" 'Already installed "tmux-copycat"' ||
 		fail_helper "[script] multiple plugins already installed message fail"
 
 	teardown_helper
diff --git a/tests/test_plugin_installation_legacy.sh b/tests/test_plugin_installation_legacy.sh
index aeec737..d0bf375 100755
--- a/tests/test_plugin_installation_legacy.sh
+++ b/tests/test_plugin_installation_legacy.sh
@@ -1,15 +1,17 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+PLUGINS_DIR="$HOME/.tmux/plugins"
+TPM_DIR="$PWD"
 
-source $CURRENT_DIR/helpers.sh
+source "$CURRENT_DIR/helpers.sh"
 
 # 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 "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	# opens tmux and test it with `expect`
@@ -17,7 +19,7 @@ test_plugin_installation_via_tmux_key_binding() {
 		fail_helper "[key-binding] plugin installation fails"
 
 	# check plugin dir exists after download
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[key-binding] plugin download fails"
 
 	teardown_helper
@@ -29,7 +31,7 @@ test_legacy_and_new_syntax_for_plugin_installation_work_via_tmux_key_binding() {
 		tmux-plugins/tmux-example-plugin    \
 	"
 	set -g @plugin 'tmux-plugins/tmux-copycat'
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	# opens tmux and test it with `expect`
@@ -37,10 +39,10 @@ test_legacy_and_new_syntax_for_plugin_installation_work_via_tmux_key_binding() {
 		fail_helper "[key-binding] multiple plugins installation fails"
 
 	# check plugin dir exists after download
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[key-binding] plugin download fails (tmux-example-plugin)"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-copycat/" ||
 		fail_helper "[key-binding] plugin download fails (tmux-copycat)"
 
 	teardown_helper
@@ -51,16 +53,16 @@ test_legacy_and_new_syntax_for_plugin_installation_work_via_tmux_key_binding() {
 test_plugin_installation_via_script() {
 	set_tmux_conf_helper <<- HERE
 	set -g @tpm_plugins "tmux-plugins/tmux-example-plugin"
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
-	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" '"tmux-example-plugin" download success' ||
 		fail_helper "[script] plugin installation fails"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[script] plugin download fails"
 
-	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-example-plugin"' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" 'Already installed "tmux-example-plugin"' ||
 		fail_helper "[script] plugin already installed message fail"
 
 	teardown_helper
@@ -72,19 +74,19 @@ test_legacy_and_new_syntax_for_plugin_installation_work_via_script() {
 		tmux-plugins/tmux-example-plugin    \
 	"
 	set -g @plugin 'tmux-plugins/tmux-copycat'
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
-	script_run_helper "$PWD/bin/install_plugins" '"tmux-example-plugin" download success' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" '"tmux-example-plugin" download success' ||
 		fail_helper "[script] multiple plugin installation fails"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-example-plugin/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-example-plugin/" ||
 		fail_helper "[script] plugin download fails (tmux-example-plugin)"
 
-	check_dir_exists_helper "$HOME/.tmux/plugins/tmux-copycat/" ||
+	check_dir_exists_helper "$PLUGINS_DIR/tmux-copycat/" ||
 		fail_helper "[script] plugin download fails (tmux-copycat)"
 
-	script_run_helper "$PWD/bin/install_plugins" 'Already installed "tmux-copycat"' ||
+	script_run_helper "$TPM_DIR/bin/install_plugins" 'Already installed "tmux-copycat"' ||
 		fail_helper "[script] multiple plugins already installed message fail"
 
 	teardown_helper
diff --git a/tests/test_plugin_sourcing.sh b/tests/test_plugin_sourcing.sh
index 9cab80f..73956c7 100755
--- a/tests/test_plugin_sourcing.sh
+++ b/tests/test_plugin_sourcing.sh
@@ -1,8 +1,9 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+TPM_DIR="$PWD"
 
-source $CURRENT_DIR/helpers.sh
+source "$CURRENT_DIR/helpers.sh"
 
 check_binding_defined() {
 	local binding="$1"
@@ -12,7 +13,7 @@ check_binding_defined() {
 test_plugin_sourcing() {
 	set_tmux_conf_helper <<- HERE
 	set -g @plugin "doesnt_matter/tmux_test_plugin"
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	# manually creates a local tmux plugin
diff --git a/tests/test_plugin_update.sh b/tests/test_plugin_update.sh
index 8e135f9..bc9e8e2 100755
--- a/tests/test_plugin_update.sh
+++ b/tests/test_plugin_update.sh
@@ -1,28 +1,30 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+TPM_DIR="$PWD"
+PLUGINS_DIR="$HOME/.tmux/plugins"
 
-source $CURRENT_DIR/helpers.sh
+source "$CURRENT_DIR/helpers.sh"
 
 manually_install_the_plugin() {
-	mkdir -p ~/.tmux/plugins/
-	cd ~/.tmux/plugins/
+	mkdir -p "$PLUGINS_DIR"
+	cd "$PLUGINS_DIR"
 	git clone --quiet https://github.com/tmux-plugins/tmux-example-plugin
 }
 
 test_plugin_installation() {
 	set_tmux_conf_helper <<- HERE
 	set -g @plugin "tmux-plugins/tmux-example-plugin"
-	run-shell "$PWD/tpm"
+	run-shell "$TPM_DIR/tpm"
 	HERE
 
 	manually_install_the_plugin
 
 	# opens tmux and test it with `expect`
-	$CURRENT_DIR/expect_successful_update_of_all_plugins ||
+	"$CURRENT_DIR/expect_successful_update_of_all_plugins" ||
 		fail_helper "Tmux 'update all plugins' fails"
 
-	$CURRENT_DIR/expect_successful_update_of_a_single_plugin ||
+	"$CURRENT_DIR/expect_successful_update_of_a_single_plugin" ||
 		fail_helper "Tmux 'update single plugin' fails"
 
 	teardown_helper