Env: Allow skipping setting a configuration value by specifying it as null.

packages/env/CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 ### Enhancement
 -   Removed the need for quotation marks when passing options to `wp-env run`.
+-   Setting a `config` key to `null` will prevent adding the constant to `wp-config.php` even if a default value is defined by `wp-env`.
 
 ## 4.7.0 (2022-05-18)
 

packages/env/README.md

@@ -518,6 +518,8 @@ WP_HOME: 'http://localhost',
 
 On the test instance, all of the above are still defined, but `WP_DEBUG` and `SCRIPT_DEBUG` are set to false.
 
+These can be overridden by setting a value within the `config` configuration. Setting it to `null` will prevent the constant being defined entirely.
+
 Additionally, the values referencing a URL include the specified port for the given environment. So if you set `testsPort: 3000, port: 2000`, `WP_HOME` (for example) will be `http://localhost:3000` on the tests instance and `http://localhost:2000` on the development instance.
 
 ### Examples

packages/env/lib/wordpress.js

@@ -64,6 +64,11 @@ async function configureWordPress( environment, config, spinner ) {
 	for ( let [ key, value ] of Object.entries(
 		config.env[ environment ].config
 	) ) {
+		// Allow the configuration to skip a default constant by specifying it as null.
+		if ( null === value ) {
+			continue;
+		}
+
 		// Add quotes around string values to work with multi-word strings better.
 		value = typeof value === 'string' ? `"${ value }"` : value;
 		setupCommands.push(