Apply Travis CI improvements from #676:

- Do the client-side build before running PHPUnit tests; this ensures
  that the plugin doesn't try to enqueue non-existent JS files and cause
  a bunch of warnings
- If a step in the build fails, go ahead and exit
- Don't scan node_modules/ and vendor/ for PHP files
- Run phpcs with the `-s` option (show rule identifiers in reports)
- Don't require docblocks for unit tests

.travis.yml

@@ -51,15 +51,21 @@ before_script:
 script:
   - |
     if [[ ! -z "$WP_VERSION" ]] ; then
-      phpunit
-      WP_MULTISITE=1 phpunit
+      npm install || exit 1
+      npm run build || exit 1
+      phpunit || exit 1
+      WP_MULTISITE=1 phpunit || exit 1
     fi
   - |
     if [[ "$TRAVISCI" == "phpcs" ]] ; then
-      phpcs --standard=phpcs.ruleset.xml $(find . -name '*.php')
+      find . \
+        -not \( -path './node_modules' \) \
+        -not \( -path './vendor' \) \
+        -name '*.php' \
+      | xargs -d'\n' phpcs --standard=phpcs.ruleset.xml -s
     fi
   - |
     if [[ "$TRAVISCI" == "js" ]] ; then
-      npm install
-      npm run ci
+      npm install || exit 1
+      npm run ci || exit 1
     fi

phpcs.ruleset.xml

@@ -5,6 +5,8 @@
 	<rule ref="WordPress-Core" />
 	<rule ref="WordPress-Docs" />
 
-	<exclude-pattern>*/node_modules/*</exclude-pattern>
-	<exclude-pattern>*/vendor/*</exclude-pattern>
+	<!-- Do not require docblocks for unit tests -->
+	<rule ref="Squiz.Commenting.FunctionComment.Missing">
+		<exclude-pattern>phpunit/*</exclude-pattern>
+	</rule>
 </ruleset>