diff --git a/.travis.yml b/.travis.yml
index ebc211463d9..1977e9b9b16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
 language: php
+dist: trusty
 
 addons:
   chrome: stable
@@ -8,6 +9,11 @@ addons:
 
 sudo: false
 
+cache:
+  directories:
+    - vendor
+    - $HOME/.composer/cache
+
 # Test main supported versions of PHP against latest WP.
 php:
   - 5.6
@@ -45,6 +51,7 @@ matrix:
     env: WP_VERSION=latest WP_MULTISITE=0 RUN_CODE_COVERAGE=1
 
 before_script:
+  - export PATH="$HOME/.composer/vendor/bin:$PATH"
   - |
     # Remove Xdebug for a huge performance increase:
     if [ -f ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini ]; then
@@ -52,9 +59,18 @@ before_script:
     else
       echo "xdebug.ini does not exist"
     fi
-  - export PATH="$HOME/.config/composer/vendor/bin:$PATH"
-  - bash tests/bin/install.sh woocommerce_test root '' localhost $WP_VERSION
-  - bash tests/bin/travis.sh before
+  - |
+    # Install WP Test suite, install PHPUnit globally if needed:
+    if [[ ! -z "$WP_VERSION" ]] ; then
+      bash tests/bin/install.sh woocommerce_test root '' localhost $WP_VERSION
+      composer global require "phpunit/phpunit=4.8.*|5.7.*"
+    fi
+  - |
+    # Install wpcs globally if needed:
+    if [[ ${RUN_PHPCS} == 1 ]]; then
+      composer global require wp-coding-standards/wpcs
+      phpcs --config-set installed_paths $HOME/.composer/vendor/wp-coding-standards/wpcs
+    fi
 
 script:
   - bash tests/bin/phpunit.sh
diff --git a/tests/bin/install.sh b/tests/bin/install.sh
index 77d081b9505..343d8930135 100755
--- a/tests/bin/install.sh
+++ b/tests/bin/install.sh
@@ -13,8 +13,10 @@ DB_HOST=${4-localhost}
 WP_VERSION=${5-latest}
 SKIP_DB_CREATE=${6-false}
 
-WP_TESTS_DIR=${WP_TESTS_DIR-/tmp/wordpress-tests-lib}
-WP_CORE_DIR=${WP_CORE_DIR-/tmp/wordpress/}
+TMPDIR=${TMPDIR-/tmp}
+TMPDIR=$(echo $TMPDIR | sed -e "s/\/$//")
+WP_TESTS_DIR=${WP_TESTS_DIR-$TMPDIR/wordpress-tests-lib}
+WP_CORE_DIR=${WP_CORE_DIR-$TMPDIR/wordpress/}
 
 download() {
     if [ `which curl` ]; then
@@ -24,8 +26,15 @@ download() {
     fi
 }
 
-if [[ $WP_VERSION =~ [0-9]+\.[0-9]+(\.[0-9]+)?(^-) ]]; then
-	WP_TESTS_TAG="tags/$WP_VERSION"
+if [[ $WP_VERSION =~ ^[0-9]+\.[0-9]+$ ]]; then
+	WP_TESTS_TAG="branches/$WP_VERSION"
+elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0-9]+ ]]; then
+	if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+		# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+		WP_TESTS_TAG="tags/${WP_VERSION%??}"
+	else
+		WP_TESTS_TAG="tags/$WP_VERSION"
+	fi
 elif [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
 	WP_TESTS_TAG="trunk"
 else
@@ -51,18 +60,34 @@ install_wp() {
 	mkdir -p $WP_CORE_DIR
 
 	if [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
-		mkdir -p /tmp/wordpress-nightly
-		download https://wordpress.org/nightly-builds/wordpress-latest.zip  /tmp/wordpress-nightly/wordpress-nightly.zip
-		unzip -q /tmp/wordpress-nightly/wordpress-nightly.zip -d /tmp/wordpress-nightly/
-		mv /tmp/wordpress-nightly/wordpress/* $WP_CORE_DIR
+		mkdir -p $TMPDIR/wordpress-nightly
+		download https://wordpress.org/nightly-builds/wordpress-latest.zip  $TMPDIR/wordpress-nightly/wordpress-nightly.zip
+		unzip -q $TMPDIR/wordpress-nightly/wordpress-nightly.zip -d $TMPDIR/wordpress-nightly/
+		mv $TMPDIR/wordpress-nightly/wordpress/* $WP_CORE_DIR
 	else
 		if [ $WP_VERSION == 'latest' ]; then
 			local ARCHIVE_NAME='latest'
+		elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+ ]]; then
+			# https serves multiple offers, whereas http serves single.
+			download https://api.wordpress.org/core/version-check/1.7/ $TMPDIR/wp-latest.json
+			if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+				# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+				LATEST_VERSION=${WP_VERSION%??}
+			else
+				# otherwise, scan the releases and get the most up to date minor version of the major release
+				local VERSION_ESCAPED=`echo $WP_VERSION | sed 's/\./\\\\./g'`
+				LATEST_VERSION=$(grep -o '"version":"'$VERSION_ESCAPED'[^"]*' $TMPDIR/wp-latest.json | sed 's/"version":"//' | head -1)
+			fi
+			if [[ -z "$LATEST_VERSION" ]]; then
+				local ARCHIVE_NAME="wordpress-$WP_VERSION"
+			else
+				local ARCHIVE_NAME="wordpress-$LATEST_VERSION"
+			fi
 		else
 			local ARCHIVE_NAME="wordpress-$WP_VERSION"
 		fi
-		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  /tmp/wordpress.tar.gz
-		tar --strip-components=1 -zxmf /tmp/wordpress.tar.gz -C $WP_CORE_DIR
+		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  $TMPDIR/wordpress.tar.gz
+		tar --strip-components=1 -zxmf $TMPDIR/wordpress.tar.gz -C $WP_CORE_DIR
 	fi
 
 	download https://raw.github.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php
@@ -91,9 +116,7 @@ install_test_suite() {
 		sed $ioption "s:dirname( __FILE__ ) . '/src/':'$WP_CORE_DIR/':" "$WP_TESTS_DIR"/wp-tests-config.php
 		sed $ioption "s/youremptytestdbnamehere/$DB_NAME/" "$WP_TESTS_DIR"/wp-tests-config.php
 		sed $ioption "s/yourusernamehere/$DB_USER/" "$WP_TESTS_DIR"/wp-tests-config.php
-		# escape the regex delim if not already escaped (i.e. if preceded by an even number of backslashes)
-		E_DB_PASS=$(echo $DB_PASS | sed -E -e 's%([/&\\])%\\\1%g')
-		sed $ioption "s/yourpasswordhere/${E_DB_PASS}/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/yourpasswordhere/$DB_PASS/" "$WP_TESTS_DIR"/wp-tests-config.php
 		sed $ioption "s|localhost|${DB_HOST}|" "$WP_TESTS_DIR"/wp-tests-config.php
 	fi
 
diff --git a/tests/bin/phpcs.sh b/tests/bin/phpcs.sh
index 3556b9137c2..a148d35a2ac 100755
--- a/tests/bin/phpcs.sh
+++ b/tests/bin/phpcs.sh
@@ -6,6 +6,6 @@ if [[ ${RUN_PHPCS} == 1 ]]; then
 
 	if [ "$CHANGED_FILES" != "" ]; then
 		echo "Running Code Sniffer."
-		./vendor/bin/phpcs --ignore=$IGNORE --encoding=utf-8 -s -n -p $CHANGED_FILES
+		phpcs --ignore=$IGNORE --encoding=utf-8 -s -n -p $CHANGED_FILES
 	fi
 fi
diff --git a/tests/bin/phpunit.sh b/tests/bin/phpunit.sh
index e4924f45c08..ebc7c5b79ef 100755
--- a/tests/bin/phpunit.sh
+++ b/tests/bin/phpunit.sh
@@ -5,7 +5,7 @@ if [[ ${RUN_PHPCS} == 1 ]] || [[ ${RUN_E2E} == 1 ]]; then
 fi
 
 if [[ ${RUN_CODE_COVERAGE} == 1 ]]; then
-	phpdbg -qrr -d memory_limit=-1 $HOME/.composer/vendor/bin/phpunit -c phpunit.xml --coverage-clover=coverage.clover --exclude-group=timeout
+	phpdbg -qrr -d memory_limit=-1 phpunit -c phpunit.xml --coverage-clover=coverage.clover --exclude-group=timeout
 else
 	phpunit -c phpunit.xml
 fi
diff --git a/tests/bin/run-e2e-CI.sh b/tests/bin/run-e2e-CI.sh
index 6c4ece22b95..34d02a89396 100755
--- a/tests/bin/run-e2e-CI.sh
+++ b/tests/bin/run-e2e-CI.sh
@@ -7,7 +7,7 @@ if [[ ${RUN_E2E} == 1 ]]; then
 	export BASE_URL="$WP_SITE_URL"
 	export DISPLAY=:99.0
 	sh -e /etc/init.d/xvfb start
- 	sleep 3
+	sleep 3
 
 	# Run the tests
 	npm test
diff --git a/tests/bin/travis.sh b/tests/bin/travis.sh
index a131190d814..d1faa8d85ba 100755
--- a/tests/bin/travis.sh
+++ b/tests/bin/travis.sh
@@ -1,16 +1,6 @@
 #!/usr/bin/env bash
 # usage: travis.sh before|after
 
-if [ $1 == 'before' ]; then
-
-	composer global require "phpunit/phpunit=6.*"
-
-	if [[ ${RUN_PHPCS} == 1 ]]; then
-		composer install
-	fi
-
-fi
-
 if [ $1 == 'after' ]; then
 
 	if [[ ${RUN_CODE_COVERAGE} == 1 ]]; then
@@ -22,9 +12,9 @@ if [ $1 == 'after' ]; then
 
 	if [[ ${RUN_E2E} == 1 && $(ls -A $TRAVIS_BUILD_DIR/screenshots) ]]; then
 		if [[ -z "${ARTIFACTS_KEY}" ]]; then
-  			echo "Screenshots were not uploaded. Please run the e2e tests locally to see failures."
+			echo "Screenshots were not uploaded. Please run the e2e tests locally to see failures."
 		else
-  			curl -sL https://raw.githubusercontent.com/travis-ci/artifacts/master/install | bash
+			curl -sL https://raw.githubusercontent.com/travis-ci/artifacts/master/install | bash
 			artifacts upload
 		fi
 	fi