diff --git a/tests/phpunit/tests/ajax/DeleteComment.php b/tests/phpunit/tests/ajax/DeleteComment.php
index 82409d3b66..bd38671b0d 100644
--- a/tests/phpunit/tests/ajax/DeleteComment.php
+++ b/tests/phpunit/tests/ajax/DeleteComment.php
@@ -205,7 +205,7 @@ class Tests_Ajax_DeleteComment extends WP_Ajax_UnitTestCase {
 			$this->fail( 'Expected exception: WPAjaxDieStopException' );
 		} catch ( WPAjaxDieStopException $e ) {
 			$this->assertSame( 10, strlen( $e->getMessage() ) );
-			$this->assertTrue( is_numeric( $e->getMessage() ) );
+			$this->assertIsNumeric( $e->getMessage() );
 		} catch ( Exception $e ) {
 			$this->fail( 'Unexpected exception type: ' . get_class( $e ) );
 		}
@@ -255,7 +255,7 @@ class Tests_Ajax_DeleteComment extends WP_Ajax_UnitTestCase {
 			$this->fail( 'Expected exception: WPAjaxDieStopException' );
 		} catch ( WPAjaxDieStopException $e ) {
 			$this->assertSame( 10, strlen( $e->getMessage() ) );
-			$this->assertTrue( is_numeric( $e->getMessage() ) );
+			$this->assertIsNumeric( $e->getMessage() );
 		} catch ( Exception $e ) {
 			$this->fail( 'Unexpected exception type: ' . get_class( $e ) );
 		}
diff --git a/tests/phpunit/tests/customize/manager.php b/tests/phpunit/tests/customize/manager.php
index 8ae0c5d138..430ad49b69 100644
--- a/tests/phpunit/tests/customize/manager.php
+++ b/tests/phpunit/tests/customize/manager.php
@@ -1214,7 +1214,7 @@ class Tests_WP_Customize_Manager extends WP_UnitTestCase {
 		$this->assertSame( $manager->changeset_uuid(), get_post( $post_id )->post_name, 'Expected that the "__trashed" suffix to not be added.' );
 		wp_set_current_user( self::$admin_user_id );
 		$this->assertSame( 'publish', get_post_meta( $post_id, '_wp_trash_meta_status', true ) );
-		$this->assertTrue( is_numeric( get_post_meta( $post_id, '_wp_trash_meta_time', true ) ) );
+		$this->assertIsNumeric( get_post_meta( $post_id, '_wp_trash_meta_time', true ) );
 
 		foreach ( array_keys( $expected_actions ) as $action_name ) {
 			$this->assertSame( $expected_actions[ $action_name ] + $action_counts[ $action_name ], did_action( $action_name ), "Action: $action_name" );
diff --git a/tests/phpunit/tests/functions.php b/tests/phpunit/tests/functions.php
index 02bc5e7e9a..314e6d2899 100644
--- a/tests/phpunit/tests/functions.php
+++ b/tests/phpunit/tests/functions.php
@@ -1198,7 +1198,7 @@ class Tests_Functions extends WP_UnitTestCase {
 		for ( $i = 0; $i < 20; $i += 1 ) {
 			$id = wp_unique_id();
 			$this->assertIsString( $id );
-			$this->assertTrue( is_numeric( $id ) );
+			$this->assertIsNumeric( $id );
 			$ids[] = $id;
 		}
 		$this->assertSame( $ids, array_unique( $ids ) );
diff --git a/tests/phpunit/tests/post.php b/tests/phpunit/tests/post.php
index ebea603414..7923288ec0 100644
--- a/tests/phpunit/tests/post.php
+++ b/tests/phpunit/tests/post.php
@@ -79,7 +79,7 @@ class Tests_Post extends WP_UnitTestCase {
 
 			// Insert a post and make sure the ID is OK.
 			$id = wp_insert_post( $post );
-			$this->assertTrue( is_numeric( $id ) );
+			$this->assertIsNumeric( $id );
 			$this->assertTrue( $id > 0 );
 
 			// Fetch the post and make sure it matches.
@@ -135,7 +135,7 @@ class Tests_Post extends WP_UnitTestCase {
 		$id               = wp_insert_post( $post );
 		$this->post_ids[] = $id;
 		// dmp( _get_cron_array() );
-		$this->assertTrue( is_numeric( $id ) );
+		$this->assertIsNumeric( $id );
 		$this->assertTrue( $id > 0 );
 
 		// Fetch the post and make sure it matches.
@@ -258,7 +258,7 @@ class Tests_Post extends WP_UnitTestCase {
 		$id               = wp_insert_post( $post );
 		$this->post_ids[] = $id;
 		// dmp( _get_cron_array() );
-		$this->assertTrue( is_numeric( $id ) );
+		$this->assertIsNumeric( $id );
 		$this->assertTrue( $id > 0 );
 
 		// Fetch the post and make sure it matches.
@@ -379,7 +379,7 @@ class Tests_Post extends WP_UnitTestCase {
 		$id               = wp_insert_post( $post );
 		$this->post_ids[] = $id;
 		// dmp( _get_cron_array() );
-		$this->assertTrue( is_numeric( $id ) );
+		$this->assertIsNumeric( $id );
 		$this->assertTrue( $id > 0 );
 
 		// Fetch the post and make sure it matches.
diff --git a/tests/phpunit/tests/taxonomy.php b/tests/phpunit/tests/taxonomy.php
index 241cc26a98..6469563a08 100644
--- a/tests/phpunit/tests/taxonomy.php
+++ b/tests/phpunit/tests/taxonomy.php
@@ -420,7 +420,7 @@ class Tests_Taxonomy extends WP_UnitTestCase {
 			'taxonomy' => 'category',
 			'cat_name' => 'test1',
 		);
-		$this->assertTrue( is_numeric( wp_insert_category( $cat, true ) ) );
+		$this->assertIsNumeric( wp_insert_category( $cat, true ) );
 	}
 
 	function test_insert_category_update() {
diff --git a/tests/phpunit/tests/term.php b/tests/phpunit/tests/term.php
index ce496df353..98adeb8f92 100644
--- a/tests/phpunit/tests/term.php
+++ b/tests/phpunit/tests/term.php
@@ -153,7 +153,7 @@ class Tests_Term extends WP_UnitTestCase {
 		$initial_count = wp_count_terms( array( 'taxonomy' => 'category' ) );
 
 		$t = wp_insert_category( array( 'cat_name' => $term ) );
-		$this->assertTrue( is_numeric( $t ) );
+		$this->assertIsNumeric( $t );
 		$this->assertNotWPError( $t );
 		$this->assertTrue( $t > 0 );
 		$this->assertEquals( $initial_count + 1, wp_count_terms( array( 'taxonomy' => 'category' ) ) );
diff --git a/tests/phpunit/tests/theme/getThemeStarterContent.php b/tests/phpunit/tests/theme/getThemeStarterContent.php
index df59f83e17..4266bbef93 100644
--- a/tests/phpunit/tests/theme/getThemeStarterContent.php
+++ b/tests/phpunit/tests/theme/getThemeStarterContent.php
@@ -159,7 +159,7 @@ class Tests_Theme_GetThemeStarterContent extends WP_UnitTestCase {
 
 		foreach ( $hydrated_starter_content['posts'] as $key => $post ) {
 			$this->assertIsString( $key );
-			$this->assertFalse( is_numeric( $key ) );
+			$this->assertIsNotNumeric( $key );
 			$this->assertIsArray( $post );
 			$this->assertArrayHasKey( 'post_type', $post );
 			$this->assertArrayHasKey( 'post_title', $post );
diff --git a/tests/phpunit/tests/user.php b/tests/phpunit/tests/user.php
index f5ba3982e2..2e599e7ef4 100644
--- a/tests/phpunit/tests/user.php
+++ b/tests/phpunit/tests/user.php
@@ -482,7 +482,7 @@ class Tests_User extends WP_UnitTestCase {
 
 		// Insert a post and make sure the ID is OK.
 		$post_id = wp_insert_post( $post );
-		$this->assertTrue( is_numeric( $post_id ) );
+		$this->assertIsNumeric( $post_id );
 
 		setup_postdata( get_post( $post_id ) );
 
diff --git a/tests/phpunit/tests/user/wpDeleteUser.php b/tests/phpunit/tests/user/wpDeleteUser.php
index 8bbf351bb2..6c8aa8b6ce 100644
--- a/tests/phpunit/tests/user/wpDeleteUser.php
+++ b/tests/phpunit/tests/user/wpDeleteUser.php
@@ -67,7 +67,7 @@ class Tests_User_WpDeleteUser extends WP_UnitTestCase {
 
 		// Insert a post and make sure the ID is OK.
 		$post_id = wp_insert_post( $post );
-		$this->assertTrue( is_numeric( $post_id ) );
+		$this->assertIsNumeric( $post_id );
 		$this->assertTrue( $post_id > 0 );
 
 		$post = get_post( $post_id );
@@ -83,7 +83,7 @@ class Tests_User_WpDeleteUser extends WP_UnitTestCase {
 
 		// Insert a post and make sure the ID is OK.
 		$nav_id = wp_insert_post( $post );
-		$this->assertTrue( is_numeric( $nav_id ) );
+		$this->assertIsNumeric( $nav_id );
 		$this->assertTrue( $nav_id > 0 );
 
 		$post = get_post( $nav_id );