Tests: add dedicated tests for the wp_parse_str() function

Even though the function doesn't really contain any logic, these tests document the function behaviour when different input values and output values are passed and safeguard PHP cross-version compatibility.

Author: jrfnl

tests/phpunit/tests/formatting/WpParseStr.php

@@ -0,0 +1,144 @@
+<?php
+
+/**
+ * @group formatting.php
+ * @covers ::wp_parse_str
+ */
+class Tests_Formatting_WpParseStr extends WP_UnitTestCase {
+
+	/**
+	 * Tests parsing of a string into variables.
+	 *
+	 * Note: while the function under test does not contain any significant logic,
+	 * these tests document the behaviour and safeguard PHP cross-version compatibility.
+	 *
+	 * @dataProvider data_wp_parse_str
+	 *
+	 * @param mixed $input    Value to parse.
+	 * @param array $expected Expected function output.
+	 */
+	public function test_wp_parse_str( $input, $expected ) {
+		wp_parse_str( $input, $output );
+		$this->assertSame( $expected, $output );
+	}
+
+	/**
+	 * Data Provider.
+	 *
+	 * @return array
+	 */
+	public function data_wp_parse_str() {
+		return array(
+			'null'          => array(
+				'input'    => null,
+				'expected' => array(),
+			),
+			'boolean false' => array(
+				'input'    => false,
+				'expected' => array(),
+			),
+			'boolean true'  => array(
+				'input'    => true,
+				'expected' => array(
+					1 => '',
+				),
+			),
+			'integer 0'     => array(
+				'input'    => 0,
+				'expected' => array(
+					0 => '',
+				),
+			),
+			'integer 456'   => array(
+				'input'    => 456,
+				'expected' => array(
+					456 => '',
+				),
+			),
+			'float 12.53'   => array(
+				'input'    => 12.53,
+				'expected' => array(
+					'12_53' => '',
+				),
+			),
+			'plain string'  => array(
+				'input'    => 'foobar',
+				'expected' => array(
+					'foobar' => '',
+				),
+			),
+			'query string'  => array(
+				'input'    => 'x=5&_baba=dudu&',
+				'expected' => array(
+					'x'     => '5',
+					'_baba' => 'dudu',
+				),
+			),
+			'stringable object'  => array(
+				'input'    => new Fixture_Formatting_WpParseStr(),
+				'expected' => array(
+					'foobar' => '',
+				),
+			),
+		);
+	}
+
+	/**
+	 * Tests that the result array only contains the result of the string parsing
+	 * when provided with different types of "result" arrays.
+	 *
+	 * @dataProvider data_wp_parse_str_result_array_is_always_overwritten
+	 *
+	 * @param array|null $output   Value for the $output parameter.
+	 * @param array      $expected Expected function output.
+	 */
+	public function test_wp_parse_str_result_array_is_always_overwritten( $output, $expected ) {
+		wp_parse_str( 'key=25&thing=text', $output );
+		$this->assertSame( $expected, $output );
+	}
+
+	/**
+	 * Data Provider.
+	 *
+	 * @return array
+	 */
+	public function data_wp_parse_str_result_array_is_always_overwritten() {
+		// Standard value for expected output.
+		$expected = array(
+			'key'   => '25',
+			'thing' => 'text',
+		);
+
+		return array(
+			'output null'                                 => array(
+				'output'   => null,
+				'expected' => $expected,
+			),
+			'output empty array'                          => array(
+				'output'   => array(),
+				'expected' => $expected,
+			),
+			'output non empty array, no conflicting keys' => array(
+				'output'   => array(
+					'foo' => 'bar',
+				),
+				'expected' => $expected,
+			),
+			'output non empty array, conflicting keys'    => array(
+				'output'   => array(
+					'key' => 'value',
+				),
+				'expected' => $expected,
+			),
+		);
+	}
+}
+
+/**
+ * Fixture for use in the tests.
+ */
+class Fixture_Formatting_WpParseStr {
+	public function __toString() {
+		return 'foobar';
+	}
+}