Additional unit tests for statistical functions, with a fix to ordering for RANK() (#1813)

* Additional unit tests for statistical functions, with a fix to ordering for RANK()

src/PhpSpreadsheet/Calculation/Statistical.php

@@ -2868,6 +2868,9 @@ class Statistical
      * PERCENTRANK.
      *
      * Returns the rank of a value in a data set as a percentage of the data set.
+     * Note that the returned rank is simply rounded to the appropriate significant digits,
+     *      rather than floored (as MS Excel), so value 3 for a value set of  1, 2, 3, 4 will return
+     *      0.667 rather than 0.666
      *
      * @param float[] $valueSet An array of, or a reference to, a list of numbers
      * @param int $value the number whose rank you want to find
@@ -3037,10 +3040,11 @@ class Statistical
         }
 
         if ($order == 0) {
-            rsort($valueSet, SORT_NUMERIC);
-        } else {
             sort($valueSet, SORT_NUMERIC);
+        } else {
+            rsort($valueSet, SORT_NUMERIC);
         }
+
         $pos = array_search($value, $valueSet);
         if ($pos === false) {
             return Functions::NA();

tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/PercentRankTest.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class PercentRankTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerPERCENTRANK
+     *
+     * @param mixed $expectedResult
+     * @param mixed[] $valueSet
+     * @param mixed $value
+     * @param mixed $digits
+     */
+    public function testPERCENTRANK($expectedResult, $valueSet, $value, $digits = 3): void
+    {
+        $result = Statistical::PERCENTRANK($valueSet, $value, $digits);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerPERCENTRANK()
+    {
+        return require 'tests/data/Calculation/Statistical/PERCENTRANK.php';
+    }
+}

tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/PercentileTest.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class PercentileTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerPERCENTILE
+     *
+     * @param mixed $expectedResult
+     */
+    public function testPERCENTILE($expectedResult, ...$args): void
+    {
+        $result = Statistical::PERCENTILE(...$args);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerPERCENTILE()
+    {
+        return require 'tests/data/Calculation/Statistical/PERCENTILE.php';
+    }
+}

tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/QuartileTest.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class QuartileTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerQUARTILE
+     *
+     * @param mixed $expectedResult
+     */
+    public function testQUARTILE($expectedResult, ...$args): void
+    {
+        $result = Statistical::QUARTILE(...$args);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerQUARTILE()
+    {
+        return require 'tests/data/Calculation/Statistical/QUARTILE.php';
+    }
+}

tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/RankTest.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class RankTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerRANK
+     *
+     * @param mixed $expectedResult
+     * @param mixed $value
+     * @param mixed[] $valueSet
+     * @param mixed $order
+     */
+    public function testRANK($expectedResult, $value, $valueSet, $order = 0): void
+    {
+        $result = Statistical::RANK($value, $valueSet, $order);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerRANK()
+    {
+        return require 'tests/data/Calculation/Statistical/RANK.php';
+    }
+}

tests/data/Calculation/Statistical/PERCENTILE.php

@@ -0,0 +1,28 @@
+<?php
+
+return [
+    [
+        1.9,
+        [1, 2, 3, 4, 0.3],
+    ],
+    [
+        3.4,
+        [1, 2, 3, 4, 0.8],
+    ],
+    [
+        3.25,
+        [1, 2, 3, 4, 0.75],
+    ],
+    [
+        8.05,
+        [7, 8, 9, 20, 0.35],
+    ],
+    [
+        8.1,
+        [10.5, 7.2, 200, 5.4, 8.1, 0.5],
+    ],
+    [
+        48.4,
+        [10.5, 7.2, 200, 5.4, 8.1, 0.8],
+    ],
+];

tests/data/Calculation/Statistical/PERCENTRANK.php

@@ -0,0 +1,52 @@
+<?php
+
+return [
+    [
+        0.667,
+        [1, 2, 3, 4],
+        3,
+    ],
+    [
+        0.67,
+        [1, 2, 3, 4],
+        3,
+        2,
+    ],
+    [
+        0.83,
+        [1, 2, 3, 4],
+        3.5,
+        2,
+    ],
+    [
+        0.758,
+        [7, 8, 9, 20],
+        12,
+    ],
+    [
+        0.2222,
+        [10.5, 7.2, 200, 5.4, 8.1],
+        7,
+        4,
+    ],
+    [
+        0.333,
+        [13, 12, 11, 8, 4, 3, 2, 1, 1, 1],
+        2,
+    ],
+    [
+        0.556,
+        [13, 12, 11, 8, 4, 3, 2, 1, 1, 1],
+        4,
+    ],
+    [
+        0.667,
+        [13, 12, 11, 8, 4, 3, 2, 1, 1, 1],
+        8,
+    ],
+    [
+        0.583,
+        [13, 12, 11, 8, 4, 3, 2, 1, 1, 1],
+        5,
+    ],
+];

tests/data/Calculation/Statistical/QUARTILE.php

@@ -0,0 +1,40 @@
+<?php
+
+return [
+    [
+        3.5,
+        [1, 2, 4, 7, 8, 9, 10, 12, 1],
+    ],
+    [
+        5.4,
+        [10.5, 7.2, 200, 5.4, 8.1, 0],
+    ],
+    [
+        7.2,
+        [10.5, 7.2, 200, 5.4, 8.1, 1],
+    ],
+    [
+        8.1,
+        [10.5, 7.2, 200, 5.4, 8.1, 2],
+    ],
+    [
+        10.5,
+        [10.5, 7.2, 200, 5.4, 8.1, 3],
+    ],
+    [
+        200,
+        [10.5, 7.2, 200, 5.4, 8.1, 4],
+    ],
+    [
+        7.75,
+        [7, 8, 9, 10, 1],
+    ],
+    [
+        8.5,
+        [7, 8, 9, 10, 2],
+    ],
+    [
+        9.25,
+        [7, 8, 9, 10, 3],
+    ],
+];

tests/data/Calculation/Statistical/RANK.php

@@ -0,0 +1,31 @@
+<?php
+
+return [
+    [
+        3,
+        3.5,
+        [7, 3.5, 3.5, 1, 2],
+    ],
+    [
+        5,
+        7,
+        [7, 3.5, 3.5, 1, 2],
+    ],
+    [
+        2,
+        3.5,
+        [7, 3.5, 3.5, 1, 2],
+        1,
+    ],
+    [
+        1,
+        7,
+        [7, 3.5, 3.5, 1, 2],
+        1,
+    ],
+    [
+        2,
+        7.2,
+        [10.5, 7.2, 200, 5.4, 8.1],
+    ],
+];