Merge pull request #20 from Katalam/sum-of

Add sum of expectation

Author: faissaloux

Diff for: README.md

@@ -1,6 +1,6 @@
 # PEST PLUGIN MATH
 
-This plugin afford math related expectations.
+This plugin affords math related expectations.
 
 
 [![Tests](https://github.com/faissaloux/pest-plugin-math/actions/workflows/tests.yml/badge.svg)](https://github.com/faissaloux/pest-plugin-math/actions/workflows/tests.yml) ![Codecov](https://img.shields.io/codecov/c/github/faissaloux/pest-plugin-math) ![Packagist Version](https://img.shields.io/packagist/v/faissaloux/pest-plugin-math) ![Packagist License](https://img.shields.io/packagist/l/faissaloux/pest-plugin-math)
@@ -88,3 +88,16 @@ Base default is euler's number.
     expect(0.69897000433602)->toBeLogarithmOf(number: 5, base: 10);
     expect(1)->not->toBeLogarithmOf(number: 1);
 ```
+
+#### `toBeSumOf()`
+```php
+    expect(6)->toBeSumOf([1, 2, 3]);
+    expect(4)->not->toBeSumOf([2, 3]);
+```
+
+#### `toBeSummationOf()`
+$$\sum\limits_n^k x * 2$$
+```php
+    expect(2)->toBeSummationOf(fn (int $x) => $x * 2, from: 0, to: 1);
+    expect(3)->not->toBeSummationOf(fn (int $x) => $x * 2, from: 0, to: 1);
+```

Diff for: src/Expectation.php

@@ -65,7 +65,7 @@ public function toBePrime(): PestExpectation
         }
 
         for ($i = 2; $i < $this->value; $i++) {
-            if ($this->value % $i == 0) {
+            if ($this->value % $i === 0) {
                 return expect(true)->toBeFalse();
             }
         }
@@ -112,8 +112,8 @@ public function toBeSqrtOf(int|float $number, ?int $precision = null): PestExpec
      */
     public function toBeFactorialOf(int $number): PestExpectation
     {
-        expect($this->value)->tobeInt();
-        expect($number >= 0)->toBeTrue();
+        expect($this->value)->tobeInt()
+            ->and($number >= 0)->toBeTrue();
 
         if ($number === 0 || $number === 1) {
             return expect($this->value === 1)->toBeTrue();
@@ -138,6 +138,23 @@ public function toBeLogarithmOf(float $number, float $base = M_E): PestExpectati
             ->and((string) $this->value === (string) log($number, $base))->toBeTrue("$this->value doesn't equal log($number, $base)");
     }
 
+    /**
+     * @param  array<int|float>  $numbers
+     * @return PestExpectation<TValue>
+     */
+    public function toBeSumOf(array $numbers): PestExpectation
+    {
+        $sum = 0;
+
+        foreach ($numbers as $number) {
+            expect($number)->toBeNumeric();
+
+            $sum += $number;
+        }
+
+        return expect($this->value === $sum)->toBeTrue("$this->value doesn't equal $sum");
+    }
+
     /**
      * @return PestExpectation<TValue>
      */
@@ -163,4 +180,20 @@ public function toBeMinOf(array $stack): PestExpectation
     {
         return expect($this->value === min($stack))->toBeTrue();
     }
+
+    /**
+     * @return PestExpectation<TValue>
+     */
+    public function toBeSummationOf(callable $step, int $from, int $to): PestExpectation
+    {
+        $sum = 0;
+
+        foreach (range($from, $to) as $i) {
+            $stepSum = $step($i);
+            expect($stepSum)->toBeNumeric();
+            $sum += $stepSum;
+        }
+
+        return expect($this->value === $sum)->toBeTrue("$this->value doesn't equal $sum");
+    }
 }

Diff for: tests/toBeSumOf.php

@@ -0,0 +1,40 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+it('passes', function (int $sum, array $numbers): void {
+    expect($sum)->toBeSumOf($numbers);
+})->with([
+    [0, []],
+    [0, [-1, 0, 1]],
+    [10, [3, '3', 4]],
+    [20, [4, 4, 4, 4, 4]],
+    [-20, [-4, -30, 14]],
+    [30, [5, 5, 5, 5, 5, 5]],
+    [40, [6, 6, 6, 6, 6, 6, 4]],
+    [50, [7, 7, 7, 7, 7, 7, 7, 1]],
+    [72, [8, 8, 8, 8, 8, 8, 8, 8, 8]],
+    [88, [9, 9, 9, 9, 9, 9, 9, 9, 9, 7]],
+    [110, [10, 10, 10, 10, 10, 10, '10', 10, 10, 10, 10]],
+]);
+
+it('passes not', function (array $numbers): void {
+    expect(1)->not->toBeSumOf($numbers);
+})->with([
+    [[2, 3]],
+    [[1, 2, 3]],
+    [[1, 2, 3, 4]],
+    [[1, 2, 3, 4, 5]],
+]);
+
+it('fails if not number on the list', function (): void {
+    expect(0)->toBeSumOf([2, 1, 3, 'not number', 78, 99]);
+})->throws(ExpectationFailedException::class);
+
+test('failures', function (): void {
+    expect(1)->toBeSumOf([1, 2]);
+})->throws(ExpectationFailedException::class);
+
+test('failures not', function (): void {
+    expect(2)->not->toBeSumOf([2]);
+})->throws(ExpectationFailedException::class);

Diff for: tests/toBeSummationOf.php

@@ -0,0 +1,34 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+it('passes', function (int $sum, int $from, int $to, callable $step): void {
+    expect($sum)->toBeSummationOf($step, $from, $to);
+})->with([
+    [-2, -1, 0, fn (int $i): int => $i * 2],
+    [0, 0, 0, fn (int $i): int => $i * 2],
+    [110, 0, 10, fn (int $i): int => $i * 2],
+    [110, 10, 0, fn (int $i): int => $i * 2],
+    [418, 2, 20, function (int $i): int {
+        return $i * 2;
+    }],
+]);
+
+it('passes not', function (callable $step, int $from, int $to): void {
+    expect(1)->not->toBeSummationOf($step, $from, $to);
+})->with([
+    [fn (int $i): int => $i * 2, 0, 10],
+    [fn (int $i): int => $i * 2, 2, 20],
+]);
+
+it('fails if step does not return a number', function (): void {
+    expect(0)->toBeSummationOf(fn (): string => 'not number', 0, 0);
+})->throws(ExpectationFailedException::class);
+
+test('failures', function (): void {
+    expect(1)->toBeSummationOf(fn (int $i): int => $i * 2, 0, 1);
+})->throws(ExpectationFailedException::class);
+
+test('failures not', function (): void {
+    expect(2)->not->toBeSummationOf(fn (int $i): int => $i * 2, 0, 1);
+})->throws(ExpectationFailedException::class);