diff --git a/tests/phpunit/tests/admin/includes/misc/wpHeartbeatSetSuspension.php b/tests/phpunit/tests/admin/includes/misc/wpHeartbeatSetSuspension.php
new file mode 100644
index 0000000000000..4664af6b25864
--- /dev/null
+++ b/tests/phpunit/tests/admin/includes/misc/wpHeartbeatSetSuspension.php
@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * Tests for the wp_heartbeat_set_suspension() function.
+ *
+ * @group admin
+ * @group misc
+ *
+ * @covers ::wp_heartbeat_set_suspension
+ */
+class Tests_Admin_Includes_Misc_WpHeartbeatSetSuspension extends WP_UnitTestCase {
+
+	/**
+	 * Original value of $pagenow.
+	 *
+	 * @var string
+	 */
+	private $orig_pagenow;
+
+	public function set_up() {
+		parent::set_up();
+		global $pagenow;
+		$this->orig_pagenow = $pagenow;
+	}
+
+	public function tear_down() {
+		global $pagenow;
+		$pagenow = $this->orig_pagenow;
+		parent::tear_down();
+	}
+
+	/**
+	 * Tests that wp_heartbeat_set_suspension() disables suspension on post screens.
+	 *
+	 * @dataProvider data_wp_heartbeat_set_suspension
+	 *
+	 * @ticket 65200
+	 *
+	 * @param string $pagenow_val The value for the $pagenow global.
+	 * @param string $expected    The expected value of 'suspension' in settings.
+	 */
+	public function test_wp_heartbeat_set_suspension( $pagenow_val, $expected ) {
+		global $pagenow;
+		$pagenow = $pagenow_val;
+
+		$settings = array( 'suspension' => 'initial' );
+		$result   = wp_heartbeat_set_suspension( $settings );
+
+		if ( 'disable' === $expected ) {
+			$this->assertSame( 'disable', $result['suspension'], "Suspension should be 'disable' when \$pagenow is {$pagenow_val}." );
+		} else {
+			$this->assertSame( 'initial', $result['suspension'], "Suspension should remain 'initial' when \$pagenow is {$pagenow_val}." );
+		}
+	}
+
+	/**
+	 * Data provider for test_wp_heartbeat_set_suspension.
+	 *
+	 * @return array<string, array{
+	 *     pagenow_val: string,
+	 *     expected:    string,
+	 * }>
+	 */
+	public function data_wp_heartbeat_set_suspension(): array {
+		return array(
+			'post.php'     => array(
+				'pagenow_val' => 'post.php',
+				'expected'    => 'disable',
+			),
+			'post-new.php' => array(
+				'pagenow_val' => 'post-new.php',
+				'expected'    => 'disable',
+			),
+			'index.php'    => array(
+				'pagenow_val' => 'index.php',
+				'expected'    => 'initial',
+			),
+			'edit.php'     => array(
+				'pagenow_val' => 'edit.php',
+				'expected'    => 'initial',
+			),
+		);
+	}
+}