Merge pull request #5 from chadicus/fea/concat

Add Strings::concat

README.md

@@ -41,6 +41,13 @@ The following checks that `$value` is a non-empty string.
 \TraderInteractive\Filter\Strings::filter($value);
 ```
 
+#### Strings::concat
+This filter concatenates the given $value, $prefix and $suffix and returns the resulting string.
+```php
+$value = \TraderInteractive\Filter\Strings::concat('middle', 'begining_', '_end');
+assert($value === 'begining_middle_end');
+```
+
 #### Strings::explode
 
 This filter is essentially a wrapper around the built-in [`explode`](http://www.php.net/explode) method

src/Filter/Strings.php

@@ -71,6 +71,23 @@ public static function explode($value, string $delimiter = ',')
         return explode($delimiter, $value);
     }
 
+    /**
+     * This filter prepends $prefix and appends $suffix to the string value.
+     *
+     * @param mixed  $value  The string value to which $prefix and $suffix will be added.
+     * @param string $prefix The value to prepend to the string.
+     * @param string $suffix The value to append to the string.
+     *
+     * @return string
+     *
+     * @throws FilterException Thrown if $value cannot be casted to a string.
+     */
+    public static function concat($value, string $prefix = '', string $suffix = '') : string
+    {
+        self::enforceValueCanBeCastAsString($value);
+        return "{$prefix}{$value}{$suffix}";
+    }
+
     /**
      * Strip HTML and PHP tags from a string. Unlike the strip_tags function this method will return null if a null
      * value is given. The native php function will return an empty string.

tests/Filter/StringsTest.php

@@ -267,4 +267,45 @@ public function stripTagsRemoveHtmlFromString()
         $expected = 'A string with paragraph tags';
         $this->assertSame($expected, $actual);
     }
+
+    /**
+     * @test
+     * @covers ::concat
+     */
+    public function concat()
+    {
+        $this->assertSame('prefixstringsuffix', Strings::concat('string', 'prefix', 'suffix'));
+    }
+
+    /**
+     * Verify behavior of concat() when $value is not filterable
+     *
+     * @test
+     * @covers ::concat
+     * @expectedException \TraderInteractive\Exceptions\FilterException
+     *
+     * @return void
+     */
+    public function concatValueNotFilterable()
+    {
+        Strings::concat(new \StdClass(), 'prefix', 'suffix');
+    }
+
+    /**
+     * @test
+     * @covers ::concat
+     */
+    public function concatScalarValue()
+    {
+        $this->assertSame('prefix123suffix', Strings::concat(123, 'prefix', 'suffix'));
+    }
+
+    /**
+     * @test
+     * @covers ::concat
+     */
+    public function concatObjectValue()
+    {
+        $this->assertSame('prefix' . __FILE__ . 'suffix', Strings::concat(new \SplFileInfo(__FILE__), 'prefix', 'suffix'));
+    }
 }