diff --git a/tests/phpunit/tests/formatting/formatToEdit.php b/tests/phpunit/tests/formatting/formatToEdit.php
new file mode 100644
index 0000000000000..4cb55c8ae8768
--- /dev/null
+++ b/tests/phpunit/tests/formatting/formatToEdit.php
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * Tests for the `format_to_edit()` function.
+ *
+ * @group formatting
+ *
+ * @covers ::format_to_edit
+ */
+class Tests_Formatting_FormatToEdit extends WP_UnitTestCase {
+
+	/**
+	 * Tests that format_to_edit() escapes text for textarea by default ($rich_text = false).
+	 *
+	 * @ticket 65819
+	 */
+	public function test_format_to_edit_escapes_when_rich_text_is_false() {
+		$content  = '<b>"hello" & \'world\'</b>';
+		$expected = '&lt;b&gt;&quot;hello&quot; &amp; &#039;world&#039;&lt;/b&gt;';
+
+		$this->assertSame( $expected, format_to_edit( $content ) );
+		$this->assertSame( $expected, format_to_edit( $content, false ) );
+	}
+
+	/**
+	 * Tests that format_to_edit() does not escape text when $rich_text is true.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_format_to_edit_does_not_escape_when_rich_text_is_true() {
+		$content = '<b>"hello" & \'world\'</b>';
+
+		$this->assertSame( $content, format_to_edit( $content, true ) );
+	}
+
+	/**
+	 * Tests that format_to_edit filter modifies content before escaping.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_format_to_edit_filter() {
+		add_filter(
+			'format_to_edit',
+			static function ( $text ) {
+				return $text . ' & <span>extra</span>';
+			}
+		);
+
+		$expected = 'original &amp; &lt;span&gt;extra&lt;/span&gt;';
+
+		$this->assertSame( $expected, format_to_edit( 'original' ) );
+	}
+}