diff --git .travis.yml .travis.yml
index 8c065b9e8..a89729851 100644
--- .travis.yml
+++ .travis.yml
@@ -27,6 +27,7 @@ php:
 # x.y mirrors the latest from the x.y branch
 env:
   - WP_VERSION=master BP_TRAVISCI=travis:phpunit
+  - WP_VERSION=5.7 BP_TRAVISCI=travis:phpunit
   - WP_VERSION=5.6 BP_TRAVISCI=travis:phpunit
   - WP_VERSION=5.5 BP_TRAVISCI=travis:phpunit
   - WP_VERSION=5.4 BP_TRAVISCI=travis:phpunit
@@ -98,12 +99,9 @@ before_install:
 
 # before_script: Failures in this section will result in build status 'errored'
 before_script:
-  - if [[ ${TRAVIS_PHP_VERSION:0:3} == "5.6" ]]; then composer global require --dev phpunit/phpunit ^5; composer install; fi
-  - if [[ ${TRAVIS_PHP_VERSION:0:3} == "7.2" ]]; then composer global require --dev phpunit/phpunit ^6; composer install; fi
-  - if [[ ${TRAVIS_PHP_VERSION:0:3} == "7.3" ]]; then composer global require --dev phpunit/phpunit ^6; composer install; fi
   - mkdir -p /tmp/node/node_modules
   - ln -s /tmp/node/node_modules $plugin_dir/node_modules
-  - npm install
+  - if [[ $BP_TRAVISCI != "travis:phpunit" ]]; then npm install; fi
 
 # Run tests
 script: grunt $BP_TRAVISCI
diff --git Gruntfile.js Gruntfile.js
index 9a184513d..61480c710 100644
--- Gruntfile.js
+++ Gruntfile.js
@@ -323,15 +323,15 @@ module.exports = function( grunt ) {
 		},
 		phpunit: {
 			'default': {
-				cmd: 'phpunit',
+				cmd: './vendor/phpunit/phpunit/phpunit',
 				args: ['-c', 'phpunit.xml.dist']
 			},
 			'multisite': {
-				cmd: 'phpunit',
+				cmd: './vendor/phpunit/phpunit/phpunit',
 				args: ['-c', 'tests/phpunit/multisite.xml']
 			},
 			'codecoverage': {
-				cmd: 'phpunit',
+				cmd: './vendor/phpunit/phpunit/phpunit',
 				args: ['-c', 'tests/phpunit/codecoverage.xml' ]
 			}
 		},
diff --git tests/phpunit/includes/define-constants.php tests/phpunit/includes/define-constants.php
index a2805a73a..6b40b4684 100644
--- tests/phpunit/includes/define-constants.php
+++ tests/phpunit/includes/define-constants.php
@@ -20,7 +20,7 @@ if ( ! defined( 'BP_TESTS_DIR' ) ) {
  * - Assume that we are inside of a develop.svn.wordpress.org setup, and walk
  *   up the directory tree
  */
-if ( false !== getenv( 'WP_PHPUNIT__DIR' ) ) {
+if ( false !== getenv( 'WP_PHPUNIT__DIR' ) && defined( 'BP_USE_WP_ENV_TESTS' ) ) {
 	define( 'WP_TESTS_DIR', getenv( 'WP_PHPUNIT__DIR' ) );
 	define( 'WP_ROOT_DIR', '/var/www/html' );
 } elseif ( false !== getenv( 'WP_TESTS_DIR' ) ) {