Possibility to get error message when matching fails

.travis.yml

@@ -9,4 +9,4 @@ before_script:
     - curl -s http://getcomposer.org/installer | php
     - php composer.phar --dev install
 
-script: phpunit --coverage-text
+script: bin/phpunit --coverage-text

composer.json

@@ -15,6 +15,7 @@
     ],
     "require": {
         "php": ">=5.3.0",
+        "coduo/php-to-string": "1.0.*@dev",
         "symfony/property-access": "~2.3",
         "symfony/expression-language": "~2.4"
     },

src/Coduo/PHPMatcher/Matcher.php

@@ -3,25 +3,36 @@
 
 use Coduo\PHPMatcher\Matcher\PropertyMatcher;
 
-class Matcher implements PropertyMatcher
+class Matcher
 {
     /**
      * @var Matcher\PropertyMatcher
      */
     private $matcher;
 
+    /**
+     * @param PropertyMatcher $matcher
+     */
     public function __construct(PropertyMatcher $matcher)
     {
         $this->matcher = $matcher;
     }
 
+    /**
+     * @param mixed $value
+     * @param mixed $pattern
+     * @return bool
+     */
     public function match($value, $pattern)
     {
         return $this->matcher->match($value, $pattern);
     }
 
-    public function canMatch($pattern)
+    /**
+     * @return null|string
+     */
+    public function getError()
     {
-        return true;
+        return $this->matcher->getError();
     }
 }

src/Coduo/PHPMatcher/Matcher/ArrayMatcher.php

@@ -6,15 +6,13 @@
 use Symfony\Component\PropertyAccess\Exception\NoSuchIndexException;
 use Symfony\Component\PropertyAccess\PropertyAccessor;
 
-class ArrayMatcher implements PropertyMatcher
+class ArrayMatcher extends Matcher
 {
     /**
      * @var PropertyMatcher
      */
     private $propertyMatcher;
 
-    private $paths;
-
     /**
      * @var PropertyAccessor
      */
@@ -60,6 +58,7 @@ private function iterateMatch(array $value, array $pattern)
             $path = sprintf("[%s]", $key);
 
             if (!$this->hasValue($pattern, $path)) {
+                $this->error = sprintf('There is no element under path %s in pattern array.', $path);
                 return false;
             }
             $elementPattern = $this->getValue($pattern, $path);
@@ -70,6 +69,7 @@ private function iterateMatch(array $value, array $pattern)
             }
 
             if (!is_array($element)) {
+                $this->error = $this->propertyMatcher->getError();
                 return false;
             }
 

src/Coduo/PHPMatcher/Matcher/CaptureMatcher.php

@@ -2,7 +2,7 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
-class CaptureMatcher implements PropertyMatcher, \ArrayAccess
+class CaptureMatcher extends Matcher implements \ArrayAccess
 {
     const MATCH_PATTERN = "/^:.*:$/";
 
@@ -39,6 +39,7 @@ public function offsetSet($offset, $value)
             $this->captures[$offset] = $value;
         }
     }
+
     public function offsetExists($offset)
     {
         return isset($this->captures[$offset]);

src/Coduo/PHPMatcher/Matcher/ChainMatcher.php

@@ -2,15 +2,26 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
-class ChainMatcher implements PropertyMatcher
+use Coduo\ToString\String;
+
+class ChainMatcher extends Matcher
 {
+    /**
+     * @var array|PropertyMatcher[]
+     */
     private $matchers;
 
+    /**
+     * @param array|PropertyMatcher[] $matchers
+     */
     public function __construct(array $matchers = array())
     {
         $this->matchers = $matchers;
     }
 
+    /**
+     * @param PropertyMatcher $matcher
+     */
     public function addMatcher(PropertyMatcher $matcher)
     {
         $this->matchers[] = $matcher;
@@ -26,9 +37,19 @@ public function match($value, $pattern)
                 if (true === $propertyMatcher->match($value, $pattern)) {
                     return true;
                 }
+
+                $this->error = $propertyMatcher->getError();
             }
         }
 
+        if (!isset($this->error)) {
+            $this->error = sprintf(
+                'Any matcher from chain can\'t match value "%s" to pattern "%s"',
+                new String($value),
+                new String($pattern)
+            );
+        }
+
         return false;
     }
 
@@ -39,5 +60,4 @@ public function canMatch($pattern)
     {
         return true;
     }
-
 }

src/Coduo/PHPMatcher/Matcher/ExpressionMatcher.php

@@ -2,9 +2,10 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
+use Coduo\ToString\String;
 use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
 
-class ExpressionMatcher implements PropertyMatcher
+class ExpressionMatcher extends Matcher
 {
     const MATCH_PATTERN = "/^expr\((.*?)\)$/";
 
@@ -15,8 +16,13 @@ public function match($value, $pattern)
     {
         $language = new ExpressionLanguage();
         preg_match(self::MATCH_PATTERN, $pattern, $matches);
+        $expressionResult = $language->evaluate($matches[1], array('value' => $value));
 
-        return $language->evaluate($matches[1], array('value' => $value));
+        if (!$expressionResult) {
+            $this->error = sprintf("\"%s\" expression fails for value \"%s\".", $pattern, new String($value));
+        }
+
+        return $expressionResult;
     }
 
     /**

src/Coduo/PHPMatcher/Matcher/JsonMatcher.php

@@ -2,7 +2,7 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
-class JsonMatcher implements PropertyMatcher
+class JsonMatcher extends Matcher
 {
     const TRANSFORM_QUOTATION_PATTERN = '/([^"])@(integer|string|array|double|wildcard|boolean)@([^"])/';
     const TRANSFORM_QUOTATION_REPLACEMENT = '$1"@$2@"$3';
@@ -30,8 +30,13 @@ public function match($value, $pattern)
         }
 
         $pattern = $this->transformPattern($pattern);
+        $match = $this->matcher->match(json_decode($value, true), json_decode($pattern, true));
+        if (!$match) {
+            $this->error = $this->matcher->getError();
+            return false;
+        }
 
-        return $this->matcher->match(json_decode($value, true), json_decode($pattern, true));
+        return true;
     }
 
     /**

src/Coduo/PHPMatcher/Matcher/Matcher.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Coduo\PHPMatcher\Matcher;
+
+abstract class Matcher implements PropertyMatcher
+{
+    /**
+     * @var string|null
+     */
+    protected $error;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getError()
+    {
+        return $this->error;
+    }
+}

src/Coduo/PHPMatcher/Matcher/PropertyMatcher.php

@@ -21,4 +21,10 @@ public function match($value, $pattern);
      */
     public function canMatch($pattern);
 
+    /**
+     * Returns a string description why matching failed
+     *
+     * @return null|string
+     */
+    public function getError();
 }

src/Coduo/PHPMatcher/Matcher/ScalarMatcher.php

@@ -2,14 +2,21 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
-class ScalarMatcher implements PropertyMatcher
+use Coduo\ToString\String;
+
+class ScalarMatcher extends Matcher
 {
     /**
      * {@inheritDoc}
      */
     public function match($value, $pattern)
     {
-        return $value === $pattern;
+        if ($value !== $pattern) {
+            $this->error = sprintf("\"%s\" does not match \"%s\".", new String($value), new String($pattern));
+            return false;
+        }
+
+        return true;
     }
 
     /**

src/Coduo/PHPMatcher/Matcher/TypeMatcher.php

@@ -2,7 +2,9 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
-class TypeMatcher implements PropertyMatcher
+use Coduo\ToString\String;
+
+class TypeMatcher extends Matcher
 {
     const MATCH_PATTERN = "/^@(string|integer|boolean|double|array)@$/";
 
@@ -11,7 +13,12 @@ class TypeMatcher implements PropertyMatcher
      */
     public function match($value, $pattern)
     {
-        return gettype($value) === $this->extractType($pattern);
+        if (gettype($value) !== $this->extractType($pattern)) {
+            $this->error = sprintf("%s \"%s\" does not match %s pattern.", gettype($value), new String($value), $pattern);
+            return false;
+        }
+
+        return true;
     }
 
     /**
@@ -22,6 +29,7 @@ public function canMatch($pattern)
         return is_string($pattern) && 0 !== preg_match(self::MATCH_PATTERN, $pattern);
     }
 
+
     private function extractType($pattern)
     {
         return str_replace("@", "", $pattern);

src/Coduo/PHPMatcher/Matcher/WildcardMatcher.php

@@ -2,7 +2,7 @@
 
 namespace Coduo\PHPMatcher\Matcher;
 
-class WildcardMatcher implements PropertyMatcher
+class WildcardMatcher extends Matcher
 {
     const MATCH_PATTERN = "/^@(\*|wildcard)@$/";
 
@@ -21,5 +21,4 @@ public function canMatch($pattern)
     {
         return is_string($pattern) && 0 !== preg_match(self::MATCH_PATTERN, $pattern);
     }
-
 }

tests/Coduo/PHPMatcher/Matcher/ArrayMatcherTest.php

@@ -50,6 +50,18 @@ public function test_negative_match_when_cant_find_matcher_that_can_match_array_
         $this->assertFalse($matcher->match(array('test' => 1), array('test' => 1)));
     }
 
+    public function test_error_when_path_does_not_exist()
+    {
+        $this->assertFalse($this->matcher->match(array('foo' => 'foo value'), array('bar' => 'bar value')));
+        $this->assertEquals($this->matcher->getError(), 'There is no element under path [foo] in pattern array.');
+    }
+
+    public function test_error_when_matching_fail()
+    {
+        $this->assertFalse($this->matcher->match(array('foo' => 'foo value'), array('foo' => 'bar value')));
+        $this->assertEquals($this->matcher->getError(), '"foo value" does not match "bar value".');
+    }
+
     public static function positiveMatchData()
     {
         $simpleArr =  array(