[TASK] Add method removeParam to AbstractQuery (#617)

* Add's the method removeParam to the AbstractQuery class
* Add's unit tests for the method

Fixes: #579

src/Core/Query/AbstractQuery.php

@@ -156,6 +156,24 @@ abstract class AbstractQuery extends Configurable implements QueryInterface
         return $this;
     }
 
+    /**
+     * Removes a param that was previously added by addParam.
+     *
+     * Note: This can not be used to remove known default parameters of the solarium api.
+     *
+     * @param string $name
+     *
+     * @return self Provides fluent interface
+     */
+    public function removeParam($name)
+    {
+        if (isset($this->params[$name])) {
+            unset($this->params[$name]);
+        }
+
+        return $this;
+    }
+
     /**
      * Get extra params.
      *

tests/Core/Query/QueryTest.php

@@ -45,6 +45,22 @@ class QueryTest extends TestCase
         );
     }
 
+    public function testAddAndRemoveParam()
+    {
+        $query = new TestQuery();
+        $query->addParam('foo', 'bar');
+        $this->assertSame('bar', $query->getParams()['foo']);
+        $query->removeParam('foo');
+        $this->assertEmpty($query->getParams());
+    }
+
+    public function testRemoveUnknownParamDoesNotTriggerError()
+    {
+        $query = new TestQuery();
+        $query->removeParam('unknown');
+        $this->assertEmpty($query->getParams());
+    }
+
     public function testGetDefaultResponseWriter()
     {
         $query = new TestQuery();