public function testGetSystemVariableValues()
 {
     $provider1 = $this->getMock('Oro\\Bundle\\EmailBundle\\Provider\\SystemVariablesProviderInterface');
     $provider1->expects($this->once())->method('getVariableValues')->will($this->returnValue(['var1' => 'val1']));
     $provider2 = $this->getMock('Oro\\Bundle\\EmailBundle\\Provider\\SystemVariablesProviderInterface');
     $provider2->expects($this->once())->method('getVariableValues')->will($this->returnValue(['var2' => 'val2']));
     $this->provider->addSystemVariablesProvider($provider1);
     $this->provider->addSystemVariablesProvider($provider2);
     $result = $this->provider->getSystemVariableValues();
     $this->assertEquals(['var1' => 'val1', 'var2' => 'val2'], $result);
 }