fix: trim whitespace from --exclude parameter values

features/checksum-core.feature

@@ -312,3 +312,19 @@ Feature: Validate checksums for WordPress install
       Success: WordPress installation verifies against checksums.
       """
     And the return code should be 0
+
+  Scenario: Verify core checksums with excluded files containing spaces
+    Given a WP install
+    And "WordPress" replaced with "PressWord" in the readme.html file
+    And a wp-includes/some-filename.php file:
+      """
+      sample content of some file
+      """
+
+    When I try `wp core verify-checksums --exclude='readme.html, wp-includes/some-filename.php'`
+    Then STDERR should be empty
+    And STDOUT should be:
+      """
+      Success: WordPress installation verifies against checksums.
+      """
+    And the return code should be 0

features/checksum-plugin.feature

@@ -291,3 +291,27 @@ Feature: Validate checksums for WordPress plugins
       Warning: Must-use plugin 'custom-mu-plugin.php' appears to be a custom file or loader plugin and cannot be verified.
       """
     And STDOUT should match /Success: Verified \d of \d plugins \(\d skipped\)\./
+
+  Scenario: Plugin verification is skipped when the --exclude argument contains spaces
+    Given a WP install
+
+    When I run `wp plugin delete --all`
+    Then STDOUT should contain:
+      """
+      Success:
+      """
+
+    When I run `wp plugin install akismet --ignore-requirements`
+    Then STDOUT should contain:
+      """
+      Success:
+      """
+
+    When I run `wp plugin install duplicate-post --version=3.2.1 --ignore-requirements`
+    Then STDOUT should contain:
+      """
+      Success:
+      """
+
+    When I try `wp plugin verify-checksums --all --exclude='akismet, duplicate-post'`
+    Then STDOUT should match /^Success: Verified \d of \d plugins \(\d skipped\)\./

src/Checksum_Core_Command.php

@@ -126,7 +126,7 @@ public function __invoke( $args, $assoc_args ) {
 		if ( ! empty( $assoc_args['exclude'] ) ) {
 			$exclude = Utils\get_flag_value( $assoc_args, 'exclude', '' );
 
-			$this->exclude_files = explode( ',', $exclude );
+			$this->exclude_files = array_map( 'trim', explode( ',', $exclude ) );
 		}
 
 		if ( empty( $wp_version ) ) {

src/Checksum_Plugin_Command.php

@@ -103,7 +103,7 @@ public function __invoke( $args, $assoc_args ) {
 			WP_CLI::error( 'You need to specify either one or more plugin slugs to check or use the --all flag to check all plugins.' );
 		}
 
-		$exclude_list = explode( ',', $exclude );
+		$exclude_list = array_map( 'trim', explode( ',', $exclude ) );
 
 		$skips = 0;