Merge branch 'hotfix/218'

Close #218
Fixes #215

Author: weierophinney

CHANGELOG.md

@@ -22,7 +22,7 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Fixed
 
-- Nothing.
+- [#218](https://github.com/zendframework/zend-validator/pull/218) fixes a precision issue with the `Step` validator.
 
 ## 2.10.2 - 2018-02-01
 

src/Step.php

@@ -122,7 +122,9 @@ public function isValid($value)
 
         $this->setValue($value);
 
-        $fmod = $this->fmod($value - $this->baseValue, $this->step);
+        $substract = $this->sub($value, $this->baseValue);
+
+        $fmod = $this->fmod($substract, $this->step);
 
         if ($fmod !== 0.0 && $fmod !== $this->step) {
             $this->error(self::NOT_STEP);
@@ -146,10 +148,31 @@ protected function fmod($x, $y)
         }
 
         //find the maximum precision from both input params to give accurate results
-        $xFloatSegment = substr($x, strpos($x, '.') + 1) ?: '';
-        $yFloatSegment = substr($y, strpos($y, '.') + 1) ?: '';
-        $precision = strlen($xFloatSegment) + strlen($yFloatSegment);
+        $precision = $this->getPrecision($x) + $this->getPrecision($y);
 
         return round($x - $y * floor($x / $y), $precision);
     }
+
+    /**
+     * replaces the internal substraction operation which give wrong results on some cases
+     *
+     * @param float $x
+     * @param float $y
+     * @return float
+     */
+    private function sub($x, $y)
+    {
+        $precision = $this->getPrecision($x) + $this->getPrecision($y);
+        return round($x - $y, $precision);
+    }
+
+    /**
+     * @param  float $float
+     * @return int
+     */
+    private function getPrecision($float)
+    {
+        $segment = substr($float, strpos($float, '.') + 1);
+        return $segment ? strlen($segment) : 0;
+    }
 }

test/StepTest.php

@@ -124,6 +124,29 @@ public function testDecimalStep($value, $expected)
         $this->assertSame($expected, $validator->isValid($value));
     }
 
+
+    public function decimalStepSubstractionBugValues()
+    {
+        return [
+            'base-value-20' => [20, 20.06, true],
+            'base-value-40' => [40, 40.09, true],
+            'base-value-50' => [50, 50.09, true],
+        ];
+    }
+
+    /**
+     * @dataProvider decimalStepSubstractionBugValues
+     */
+    public function testDecimalStepSubstractionBug($baseValue, $value, $expected)
+    {
+        $validator = new Validator\Step([
+            'baseValue' => $baseValue,
+            'step'      => 0.01
+        ]);
+
+        $this->assertSame($expected, $validator->isValid($value));
+    }
+
     public function decimalHundredthStepValues()
     {
         return [
@@ -151,7 +174,7 @@ public function decimalHundredthStepValues()
     /**
      * @dataProvider decimalHundredthStepValues
      */
-    public function testDecimalStep2($value, $expected)
+    public function testdecimalHundredthStep($value, $expected)
     {
         $validator = new Validator\Step([
             'baseValue' => 0,