diff --git a/composer.json b/composer.json
index f2a9503e80..4997175bfe 100644
--- a/composer.json
+++ b/composer.json
@@ -16,8 +16,7 @@
 		"dealerdirect/phpcodesniffer-composer-installer": "^0.6.2 || ^0.7.0",
 		"wp-coding-standards/wpcs": "~2.3.0",
 		"phpcompatibility/phpcompatibility-wp": "^2.1.0",
-		"phpunit/phpunit": "^7.5",
-		"ext-gd": "*"
+		"phpunit/phpunit": "^7.5"
 	},
 	"autoload-dev": {
 		"files": [
diff --git a/composer.lock b/composer.lock
index 14bdf41411..007bbf83ea 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "fcf040d9233a22165eeffaeb98694436",
+    "content-hash": "463db2b4afb439fb63d93173c0852e27",
     "packages": [],
     "packages-dev": [
         {
@@ -131,20 +131,6 @@
                 "constructor",
                 "instantiate"
             ],
-            "funding": [
-                {
-                    "url": "https://www.doctrine-project.org/sponsorship.html",
-                    "type": "custom"
-                },
-                {
-                    "url": "https://www.patreon.com/phpdoctrine",
-                    "type": "patreon"
-                },
-                {
-                    "url": "https://tidelift.com/funding/github/packagist/doctrine%2Finstantiator",
-                    "type": "tidelift"
-                }
-            ],
             "time": "2020-05-29T17:27:14+00:00"
         },
         {
@@ -1851,8 +1837,6 @@
     "platform": {
         "php": ">=5.6"
     },
-    "platform-dev": {
-        "ext-gd": "*"
-    },
+    "platform-dev": [],
     "plugin-api-version": "1.1.0"
 }
diff --git a/tests/phpunit/includes/bootstrap.php b/tests/phpunit/includes/bootstrap.php
index 8cfb86afbc..36f54541b2 100644
--- a/tests/phpunit/includes/bootstrap.php
+++ b/tests/phpunit/includes/bootstrap.php
@@ -53,24 +53,27 @@ if ( version_compare( $phpunit_version, '5.4', '<' ) || version_compare( $phpuni
 	exit( 1 );
 }
 
-$required_extensions = array(
-	'gd',
-);
-$missing_extensions  = array();
-
-foreach ( $required_extensions as $extension ) {
-	if ( ! extension_loaded( $extension ) ) {
-		$missing_extensions[] = $extension;
-	}
-}
-
-if ( $missing_extensions ) {
-	printf(
-		"Error: The following required PHP extensions are missing from the testing environment: %s.\n",
-		implode( ', ', $missing_extensions )
+// If running core tests, check if all the required PHP extensions are loaded before running the test suite.
+if ( defined( 'WP_RUN_CORE_TESTS' ) && WP_RUN_CORE_TESTS ) {
+	$required_extensions = array(
+		'gd',
 	);
-	echo "Please make sure they are installed and enabled.\n",
-	exit( 1 );
+	$missing_extensions  = array();
+
+	foreach ( $required_extensions as $extension ) {
+		if ( ! extension_loaded( $extension ) ) {
+			$missing_extensions[] = $extension;
+		}
+	}
+
+	if ( $missing_extensions ) {
+		printf(
+			"Error: The following required PHP extensions are missing from the testing environment: %s.\n",
+			implode( ', ', $missing_extensions )
+		);
+		echo "Please make sure they are installed and enabled.\n",
+		exit( 1 );
+	}
 }
 
 $required_constants = array(