@@ -60,7 +60,8 @@ export WPT_SSH_PRIVATE_KEY_BASE64=""
 # Whether to enable debug Mode.
 #
 # Enabling debug mode will output verbose logging and details about each part
-# of the test runner.
+# of the test runner. It also runs npm install and build commands with
+# --loglevel=silly during preparation.
 #
 # 0 = Debug mode off
 # 1 = Debug mode on
 
@@ -241,7 +241,7 @@ export WPT_SSH_OPTIONS=""
 export WPT_SSH_PRIVATE_KEY_BASE64=""
 
 # Output logging
-# Use 'verbose' to increase verbosity
+# Use 'verbose' to increase verbosity; also runs npm with --loglevel=silly
 export WPT_DEBUG=""
 
 # Certificate validation
@@ -395,7 +395,7 @@ export WPT_SSH_PRIVATE_KEY_BASE64=""
 
 **Output logging**
 
-Output logging. Use 'verbose' to increase verbosity.
+Output logging. Use 'verbose' to increase verbosity. When set, the npm install and build commands during preparation also run with `--loglevel=silly`.
 
 ```
 export WPT_DEBUG=""
 
@@ -76,6 +76,13 @@
 }
 
 
+/*
+ * When debug mode is enabled, run npm at its most verbose logging level, so a
+ * hung or slow npm command shows what it is doing instead of sitting silent.
+ * The same debug mode adds verbosity to the rsync operations further down.
+ */
+$npm_verbosity = $runner_vars['WPT_DEBUG'] ? ' --loglevel=silly' : '';
+
 /*
  * Checkout and prepare wordpress-develop for testing.
  *
@@ -96,7 +103,7 @@
 		'git clone --depth=1 https://github.com/WordPress/wordpress-develop.git ' . escapeshellarg( $runner_vars['WPT_PREPARE_DIR'] ),
 
 		// Change directory to the preparation directory, install npm dependencies, and build the project.
-		'cd ' . escapeshellarg( $runner_vars['WPT_PREPARE_DIR'] ) . '; npm install && npm run build',
+		'cd ' . escapeshellarg( $runner_vars['WPT_PREPARE_DIR'] ) . '; npm install' . $npm_verbosity . ' && npm run build' . $npm_verbosity,
 
 	)
 );
Original file line number	Diff line number	Diff line change
`@@ -60,7 +60,8 @@ export WPT_SSH_PRIVATE_KEY_BASE64=""`
`60`	`60`	`# Whether to enable debug Mode.`
`61`	`61`	`#`
`62`	`62`	`# Enabling debug mode will output verbose logging and details about each part`
`63`		`-# of the test runner.`
	`63`	`+# of the test runner. It also runs npm install and build commands with`
	`64`	`+# --loglevel=silly during preparation.`
`64`	`65`	`#`
`65`	`66`	`# 0 = Debug mode off`
`66`	`67`	`# 1 = Debug mode on`
Original file line number	Diff line number	Diff line change
`@@ -76,6 +76,13 @@`
`76`	`76`	`}`
`77`	`77`
`78`	`78`
	`79`	`+/*`
	`80`	`+ * When debug mode is enabled, run npm at its most verbose logging level, so a`
	`81`	`+ * hung or slow npm command shows what it is doing instead of sitting silent.`
	`82`	`+ * The same debug mode adds verbosity to the rsync operations further down.`
	`83`	`+ */`
	`84`	`+$npm_verbosity = $runner_vars['WPT_DEBUG'] ? ' --loglevel=silly' : '';`
	`85`	`+`
`79`	`86`	`/*`
`80`	`87`	`* Checkout and prepare wordpress-develop for testing.`
`81`	`88`	`*`
`@@ -96,7 +103,7 @@`
`96`	`103`	`'git clone --depth=1 https://github.com/WordPress/wordpress-develop.git ' . escapeshellarg( $runner_vars['WPT_PREPARE_DIR'] ),`
`97`	`104`
`98`	`105`	`// Change directory to the preparation directory, install npm dependencies, and build the project.`
`99`		`- 'cd ' . escapeshellarg( $runner_vars['WPT_PREPARE_DIR'] ) . '; npm install && npm run build',`
	`106`	`+ 'cd ' . escapeshellarg( $runner_vars['WPT_PREPARE_DIR'] ) . '; npm install' . $npm_verbosity . ' && npm run build' . $npm_verbosity,`
`100`	`107`
`101`	`108`	`)`
`102`	`109`	`);`