diff --git a/tests/phpunit/tests/pluggable.php b/tests/phpunit/tests/pluggable.php
index 48a169e1e7..7bf32f66f5 100644
--- a/tests/phpunit/tests/pluggable.php
+++ b/tests/phpunit/tests/pluggable.php
@@ -338,114 +338,4 @@ class Tests_Pluggable extends WP_UnitTestCase {
 
 		return $signatures;
 	}
-
-	/**
-	 * @ticket 28020
-	 */
-	public function test_get_user_by_should_return_same_instance_as_wp_get_current_user() {
-		// Create a test user.
-		$new_user = self::factory()->user->create( array( 'role' => 'subscriber' ) );
-
-		// Set the test user as the current user.
-		$current_user = wp_set_current_user( $new_user );
-
-		// Get the test user using get_user_by().
-		$from_get_user_by = get_user_by( 'id', $new_user );
-
-		$this->assertSame( $current_user, $from_get_user_by );
-	}
-
-	/**
-	 * Tests that wp_rand() returns zero when `$min` and `$max` are zero.
-	 *
-	 * @ticket 55194
-	 * @dataProvider data_wp_rand_should_return_zero_when_min_and_max_are_zero
-	 * @covers ::wp_rand
-	 *
-	 * @param mixed $min Lower limit for the generated number.
-	 * @param mixed $max Upper limit for the generated number.
-	 */
-	public function test_wp_rand_should_return_zero_when_min_and_max_are_zero( $min, $max ) {
-		$this->assertSame( 0, wp_rand( $min, $max ) );
-	}
-
-	/**
-	 * Data provider.
-	 *
-	 * @return array
-	 */
-	public function data_wp_rand_should_return_zero_when_min_and_max_are_zero() {
-		return array(
-			'min and max as 0'      => array(
-				'min' => 0,
-				'max' => 0,
-			),
-			'min and max as 0.0'    => array(
-				'min' => 0.0,
-				'max' => 0.0,
-			),
-			'min as null, max as 0' => array(
-				'min' => null,
-				'max' => 0,
-			),
-		);
-	}
-
-	/**
-	 * Tests that wp_rand() returns a positive integer for both positive and negative input.
-	 *
-	 * @ticket 55194
-	 * @dataProvider data_wp_rand_should_return_a_positive_integer
-	 * @covers ::wp_rand
-	 *
-	 * @param int $min Lower limit for the generated number.
-	 * @param int $max Upper limit for the generated number.
-	 */
-	public function test_wp_rand_should_return_a_positive_integer( $min, $max ) {
-		$this->assertGreaterThan(
-			0,
-			wp_rand( $min, $max ),
-			'The value was not greater than 0'
-		);
-
-		$this->assertLessThan(
-			100,
-			wp_rand( $min, $max ),
-			'The value was not less than 100'
-		);
-	}
-
-	/**
-	 * Data provider.
-	 *
-	 * @return array
-	 */
-	public function data_wp_rand_should_return_a_positive_integer() {
-		return array(
-			'1 and 99'       => array(
-				'min' => 1,
-				'max' => 99,
-			),
-			'-1 and 99'      => array(
-				'min' => -1,
-				'max' => 99,
-			),
-			'1 and -99'      => array(
-				'min' => 1,
-				'max' => -99,
-			),
-			'-1 and -99'     => array(
-				'min' => -1,
-				'max' => -99,
-			),
-			'1.0 and 99.0'   => array(
-				'min' => 1.0,
-				'max' => 99.0,
-			),
-			'-1.0 and -99.0' => array(
-				'min' => -1.0,
-				'max' => -99.0,
-			),
-		);
-	}
 }
diff --git a/tests/phpunit/tests/pluggable/getUserBy.php b/tests/phpunit/tests/pluggable/getUserBy.php
new file mode 100644
index 0000000000..96ae8a1b5f
--- /dev/null
+++ b/tests/phpunit/tests/pluggable/getUserBy.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * @group pluggable
+ * @covers ::get_user_by
+ */
+class Tests_Pluggable_GetUserBy extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 28020
+	 */
+	public function test_get_user_by_should_return_same_instance_as_wp_get_current_user() {
+		// Create a test user.
+		$new_user = self::factory()->user->create( array( 'role' => 'subscriber' ) );
+
+		// Set the test user as the current user.
+		$current_user = wp_set_current_user( $new_user );
+
+		// Get the test user using get_user_by().
+		$from_get_user_by = get_user_by( 'id', $new_user );
+
+		$this->assertSame( $current_user, $from_get_user_by );
+	}
+}
diff --git a/tests/phpunit/tests/pluggable/wpRand.php b/tests/phpunit/tests/pluggable/wpRand.php
new file mode 100644
index 0000000000..f3092ca41b
--- /dev/null
+++ b/tests/phpunit/tests/pluggable/wpRand.php
@@ -0,0 +1,100 @@
+<?php
+
+/**
+ * @group pluggable
+ * @covers ::wp_rand
+ */
+class Tests_Pluggable_wpRand extends WP_UnitTestCase {
+
+	/**
+	 * Tests that wp_rand() returns a positive integer for both positive and negative input.
+	 *
+	 * @ticket 55194
+	 * @dataProvider data_wp_rand_should_return_a_positive_integer
+	 *
+	 * @param int $min Lower limit for the generated number.
+	 * @param int $max Upper limit for the generated number.
+	 */
+	public function test_wp_rand_should_return_a_positive_integer( $min, $max ) {
+		$this->assertGreaterThan(
+			0,
+			wp_rand( $min, $max ),
+			'The value was not greater than 0'
+		);
+
+		$this->assertLessThan(
+			100,
+			wp_rand( $min, $max ),
+			'The value was not less than 100'
+		);
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array
+	 */
+	public function data_wp_rand_should_return_a_positive_integer() {
+		return array(
+			'1 and 99'       => array(
+				'min' => 1,
+				'max' => 99,
+			),
+			'-1 and 99'      => array(
+				'min' => -1,
+				'max' => 99,
+			),
+			'1 and -99'      => array(
+				'min' => 1,
+				'max' => -99,
+			),
+			'-1 and -99'     => array(
+				'min' => -1,
+				'max' => -99,
+			),
+			'1.0 and 99.0'   => array(
+				'min' => 1.0,
+				'max' => 99.0,
+			),
+			'-1.0 and -99.0' => array(
+				'min' => -1.0,
+				'max' => -99.0,
+			),
+		);
+	}
+
+	/**
+	 * Tests that wp_rand() returns zero when `$min` and `$max` are zero.
+	 *
+	 * @ticket 55194
+	 * @dataProvider data_wp_rand_should_return_zero_when_min_and_max_are_zero
+	 *
+	 * @param mixed $min Lower limit for the generated number.
+	 * @param mixed $max Upper limit for the generated number.
+	 */
+	public function test_wp_rand_should_return_zero_when_min_and_max_are_zero( $min, $max ) {
+		$this->assertSame( 0, wp_rand( $min, $max ) );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array
+	 */
+	public function data_wp_rand_should_return_zero_when_min_and_max_are_zero() {
+		return array(
+			'min and max as 0'      => array(
+				'min' => 0,
+				'max' => 0,
+			),
+			'min and max as 0.0'    => array(
+				'min' => 0.0,
+				'max' => 0.0,
+			),
+			'min as null, max as 0' => array(
+				'min' => null,
+				'max' => 0,
+			),
+		);
+	}
+}