Add caching

.travis.yml

@@ -1,7 +1,10 @@
 language: php
 dist: trusty
 sudo: required
-
+cache:
+  directories:
+    - vendor
+    - $HOME/.composer/cache
 matrix:
   include:
   - name: "PHP 7.2 unit tests, PHP Coding standards check"
@@ -17,6 +20,5 @@ before_script:
 
 script:
   - composer install
-  - export PATH="$WP_CORE_DIR/wp-content/plugins/woocommerce-rest-api/vendor/bin:$PATH"
   - bash unit-tests/bin/phpunit.sh
   - bash unit-tests/bin/phpcs.sh

unit-tests/bin/phpunit.sh

@@ -1,9 +1,8 @@
 #!/usr/bin/env bash
 WORKING_DIR="$PWD"
-cd "$WP_CORE_DIR/wp-content/plugins/woocommerce-rest-api/"
-which phpunit
-phpunit --version
-phpunit -c phpunit.xml
+cd "$WP_CORE_DIR/wp-content/plugins/woocommerce-rest-api"
+./vendor/bin/phpunit --version
+./vendor/bin/phpunit -c phpunit.xml
 TEST_RESULT=$?
 cd "$WORKING_DIR"
 exit $TEST_RESULT